remove general section
This commit is contained in:
Nathan Wang
parent
f357195197
commit
dc142686db
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@ -1,31 +1,62 @@
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---
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id: debugging
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title: Debugging C++
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author: Benjamin Qi, Aaron Chew
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description: Detecting issues within your program and figuring out how to avoid them in the first place.
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---
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## General
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# Debugging C++
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<resources>
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<resource source="Errichto" title="Video - How to test your solution" url="https://www.youtube.com/watch?v=JXTVOyQpSGM" starred>using a script to stress test</resource>
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<resource source="Errichto" title="Asking for help FAQ" url="https://codeforces.com/blog/entry/64993" starred>some parts from above video</resource>
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<resource
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source="Errichto"
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title="Video - How to test your solution"
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url="https://www.youtube.com/watch?v=JXTVOyQpSGM"
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starred
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>
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using a script to stress test
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</resource>
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<resource
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source="Errichto"
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title="Asking for help FAQ"
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url="https://codeforces.com/blog/entry/64993"
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starred
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>
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some parts from above video
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</resource>
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</resources>
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## Within Your Program
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### Style
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### Style
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<resources>
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<resource source="CF" title="Competitive C++ Manifesto: A Style Guide" url="blog/entry/64218" starred> don't agree with everything but important to read nonetheless</resource>
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<resource
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source="CF"
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title="Competitive C++ Manifesto: A Style Guide"
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url="blog/entry/64218"
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starred
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>
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{' '}
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don't agree with everything but important to read nonetheless
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</resource>
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</resources>
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### Assertions & Warnings
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<resources>
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<resource title="Asserts" source="LearnCpp" url="https://www.learncpp.com/cpp-tutorial/7-12a-assert-and-static_assert/" starred>includes static_assert and #define NDEBUG</resource>
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<resource title="Assertions" source="GFG" url="assertions-cc">subset of above</resource>
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<resource title="Diagnostics" source="GNU" url="https://gcc.gnu.org/onlinedocs/cpp/Diagnostics.html" starred>#warning, #error</resource>
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<resource
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title="Asserts"
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source="LearnCpp"
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url="https://www.learncpp.com/cpp-tutorial/7-12a-assert-and-static_assert/"
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starred
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>
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includes static_assert and #define NDEBUG
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</resource>
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<resource title="Assertions" source="GFG" url="assertions-cc">
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subset of above
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</resource>
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<resource
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title="Diagnostics"
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source="GNU"
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url="https://gcc.gnu.org/onlinedocs/cpp/Diagnostics.html"
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starred
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>
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#warning, #error
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</resource>
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</resources>
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### Printing Variables
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@ -51,7 +82,7 @@ According to [this comment](https://codeforces.com/blog/entry/60999?#comment-449
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### [Warning Options](https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html)
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`-Wall -Wextra -Wshadow`
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`-Wall -Wextra -Wshadow`
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[Variable shadowing](https://en.wikipedia.org/wiki/Variable_shadowing) should be avoided whenever possible.
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@ -94,10 +125,10 @@ AddressSanitizer:DEADLYSIGNAL
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#1 0x7fff72208cc8 in start (libdyld.dylib:x86_64+0x1acc8)
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==31035==Register values:
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rax = 0xfffffffffffffffc rbx = 0x00007ffee913aa20 rcx = 0xfffffffffffffffc rdx = 0x20000fffffffffff
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rdi = 0x00007ffee913aa40 rsi = 0x1fffffffffffffff rbp = 0x00007ffee913aaa0 rsp = 0x00007ffee913aa20
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r8 = 0x0000000000000000 r9 = 0x0000000000000000 r10 = 0x0000000000000000 r11 = 0x0000000000000000
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r12 = 0x00000fffdd227544 r13 = 0x00007ffee913aa80 r14 = 0x00007ffee913aa20 r15 = 0x0000000000000000
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rax = 0xfffffffffffffffc rbx = 0x00007ffee913aa20 rcx = 0xfffffffffffffffc rdx = 0x20000fffffffffff
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rdi = 0x00007ffee913aa40 rsi = 0x1fffffffffffffff rbp = 0x00007ffee913aaa0 rsp = 0x00007ffee913aa20
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r8 = 0x0000000000000000 r9 = 0x0000000000000000 r10 = 0x0000000000000000 r11 = 0x0000000000000000
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r12 = 0x00000fffdd227544 r13 = 0x00007ffee913aa80 r14 = 0x00007ffee913aa20 r15 = 0x0000000000000000
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AddressSanitizer can not provide additional info.
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SUMMARY: AddressSanitizer: SEGV (prog:x86_64+0x100001325) in main
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==31035==ABORTING
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@ -109,15 +140,15 @@ Finally, `g++ prog.cpp -o prog -D_GLIBCXX_DEBUG -g && ./prog` produces:
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```
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/usr/local/Cellar/gcc/9.2.0_1/include/c++/9.2.0/debug/vector:427:
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In function:
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std::__debug::vector<_Tp, _Allocator>::reference
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std::__debug::vector<_Tp,
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_Allocator>::operator[](std::__debug::vector<_Tp,
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_Allocator>::size_type) [with _Tp = int; _Allocator =
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std::allocator<int>; std::__debug::vector<_Tp, _Allocator>::reference =
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int&; std::__debug::vector<_Tp, _Allocator>::size_type = long unsigned
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std::__debug::vector<_Tp, _Allocator>::reference
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std::__debug::vector<_Tp,
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_Allocator>::operator[](std::__debug::vector<_Tp,
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_Allocator>::size_type) [with _Tp = int; _Allocator =
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std::allocator<int>; std::__debug::vector<_Tp, _Allocator>::reference =
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int&; std::__debug::vector<_Tp, _Allocator>::size_type = long unsigned
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int]
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Error: attempt to subscript container with out-of-bounds index -1, but
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Error: attempt to subscript container with out-of-bounds index -1, but
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container only holds 0 elements.
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Objects involved in the operation:
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@ -146,8 +177,8 @@ prog.cpp:6:13: runtime error: index 5 out of bounds for type 'int [5]'
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prog.cpp:6:13: runtime error: load of address 0x7ffee0a77a94 with insufficient space for an object of type 'int'
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0x7ffee0a77a94: note: pointer points here
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b0 7a a7 e0 fe 7f 00 00 25 b0 a5 0f 01 00 00 00 b0 7a a7 e0 fe 7f 00 00 c9 8c 20 72 ff 7f 00 00
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^
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32766%
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^
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32766%
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```
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`g++ prog.cpp -o prog -fsanitize=address && ./prog` produces:
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@ -181,7 +212,7 @@ Shadow bytes around the buggy address:
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0x1fffdde1c990: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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Shadow byte legend (one shadow byte represents 8 application bytes):
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Addressable: 00
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Partially addressable: 01 02 03 04 05 06 07
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Partially addressable: 01 02 03 04 05 06 07
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Heap left redzone: fa
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Freed heap region: fd
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Stack left redzone: f1
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@ -219,9 +250,9 @@ zsh: segmentation fault ./$1
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### Measuring Time & Memory Usage
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- [CF Comment](https://codeforces.com/blog/entry/49371?#comment-333749)
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- [time -v on Mac](https://stackoverflow.com/questions/32515381/mac-os-x-usr-bin-time-verbose-flag)
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- use `gtime`
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- [CF Comment](https://codeforces.com/blog/entry/49371?#comment-333749)
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- [time -v on Mac](https://stackoverflow.com/questions/32515381/mac-os-x-usr-bin-time-verbose-flag)
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- use `gtime`
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For example, suppose that `prog.cpp` consists of the following:
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@ -277,9 +308,9 @@ You can use a [simple script](https://github.com/bqi343/USACO/blob/master/Implem
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(gdb, valgrind?)
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Using a debugger varies from language to language and even IDE to different IDE. For now I will describe the basic operations of a debugger.
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Using a debugger varies from language to language and even IDE to different IDE. For now I will describe the basic operations of a debugger.
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A debugger allows you to pause a code in its execution and see the values as a given point in the debugger.
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A debugger allows you to pause a code in its execution and see the values as a given point in the debugger.
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To do this, set a "breakpoint" at a certain line of code. When the code runs to that breakpoint, it will pause and you will be able to inspect all the different variables at that certain instance.
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@ -287,14 +318,14 @@ There are two more useful and common operations. Once you are at the breakpoint,
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In essense, a debugger is a tool to "trace code" for you. It is not much different from just printing the values out at various points in your program.
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Pros of using a debugger:
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- No need to write print statements so you save time
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- You can step through the code in real time
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Pros of using a debugger:
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- No need to write print statements so you save time
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- You can step through the code in real time
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Cons of using a debugger:
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- You cannot see the overall "output" of your program at each stage. For example, if I wanted to see every single value of `i` in the program, I could not using a debugger.
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- Most advanced competitive programmers do not use debuggers; it is quite time inefficient.
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- You cannot see the overall "output" of your program at each stage. For example, if I wanted to see every single value of `i` in the program, I could not using a debugger.
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- Most advanced competitive programmers do not use debuggers; it is quite time inefficient.
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(actual details?)
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@ -1,9 +1,4 @@
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---
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id: io-speed
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title: Input / Output Speed
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author: Benjamin Qi, Nathan Chen
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description: ""
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---
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# Input/Output
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Generally, input and output speed isn't an issue. However, some platinum tasks have relatively large input files. The [USACO Instructions Page](http://www.usaco.org/index.php?page=instructions) briefly mentions some ways of speeding up I/O; let's check that these actually make a difference.
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@ -15,9 +10,9 @@ The largest USACO input file I know of is test case 11 of [USACO Platinum - Robo
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<CPPSection>
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### Method 1: `freopen` with `cin`
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### Method 1: `freopen` with `cin`
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The slowest method.
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The slowest method.
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<spoiler title="973ms">
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@ -65,6 +60,7 @@ int main() {
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else printf("%lld",1000000000000000000LL);
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}
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```
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</spoiler>
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### Method 3: `ifstream` and `ofstream`
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@ -122,18 +118,30 @@ int main() {
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### Significance of `ios_base::sync_with_stdio(0); cin.tie(0);`
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Adding this line as the first line of `main()` reduced the runtime of the first method to 254 ms.
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Adding this line as the first line of `main()` reduced the runtime of the first method to 254 ms.
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<resources>
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<resource source="CF" url="blog/entry/5217" title="Yet again on C++ I/O" starred>timing various I/O methods</resource>
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<resource source="SO" url="https://stackoverflow.com/questions/31162367/significance-of-ios-basesync-with-stdiofalse-cin-tienull" title="Significance of [above]"> </resource>
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<resource
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source="CF"
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url="blog/entry/5217"
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title="Yet again on C++ I/O"
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starred
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>
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timing various I/O methods
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</resource>
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<resource
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source="SO"
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url="https://stackoverflow.com/questions/31162367/significance-of-ios-basesync-with-stdiofalse-cin-tienull"
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title="Significance of [above]"
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>
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{' '}
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</resource>
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</resources>
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<br />
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Actually, the former link says that it is supposedly prohibited to use `freopen` to redirect `cin` and `cout` if `ios_base::sync_with_stdio(0); cin.tie(0);` is included, but it works properly as far as I know.
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</CPPSection>
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<JavaSection>
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@ -150,20 +158,20 @@ import java.io.*;
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//3188ms
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public class roboherd_scanner {
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static int P[][] = new int[100000][];
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public static void main(String[] args) throws Exception {
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Scanner sc = new Scanner(new File("roboherd.in"));
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PrintWriter pw = new PrintWriter(new FileWriter("roboherd.out"));
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int N = sc.nextInt();
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int K = sc.nextInt();
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for(int i = 0; i < N; ++i) {
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int M = sc.nextInt(); P[i] = new int[M];
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for(int j = 0; j < M; ++j) P[i][j] = sc.nextInt();
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}
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if(N == 3) pw.println(61);
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else pw.println(1000000000000000000L);
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pw.close();
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@ -177,7 +185,7 @@ A common alternative to reading input for programming contests is [`BufferedRead
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Reading input is more complicated when multiple, space-separated values are placed in a single line. In order to individually read the values in each line, the programmer usually uses the `.split()` method in `String` or the `.nextToken()` in [`StringTokenizer`](https://docs.oracle.com/javase/8/docs/api/java/util/StringTokenizer.html). Notice that `StringTokenizer` for splitting strings is slightly faster than `.split()`. Apparently [`StreamTokenizer`](https://docs.oracle.com/javase/8/docs/api/java/io/StreamTokenizer.html) is even faster!
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*Reading input with `BufferedReader` and `.split()`*:
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_Reading input with `BufferedReader` and `.split()`_:
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<spoiler title="1209ms">
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@ -187,13 +195,13 @@ import java.io.*;
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//1209ms
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public class roboherd_buffered_reader_string_split {
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static int P[][] = new int[100000][];
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public static void main(String[] args) throws Exception {
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BufferedReader br = new BufferedReader(new FileReader("roboherd.in"));
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PrintWriter pw = new PrintWriter(new FileWriter("roboherd.out"));
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String[] tokens = br.readLine().split(" ");
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int N = Integer.parseInt(tokens[0]);
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int K = Integer.parseInt(tokens[1]);
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@ -202,17 +210,17 @@ public class roboherd_buffered_reader_string_split {
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int M = Integer.parseInt(tokens[0]); P[i] = new int[M];
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for(int j = 0; j < M; ++j) P[i][j] = Integer.parseInt(tokens[j+1]);
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}
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if(N == 3) pw.println(61);
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else pw.println(1000000000000000000L);
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pw.close();
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}
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}
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```
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</spoiler>
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*Reading input with `BufferedReader` and `StringTokenizer`*:
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_Reading input with `BufferedReader` and `StringTokenizer`_:
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<spoiler title="986ms">
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@ -222,13 +230,13 @@ import java.io.*;
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//986ms
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public class roboherd_buffered_reader_string_tokenizer {
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static int P[][] = new int[100000][];
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public static void main(String[] args) throws Exception {
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BufferedReader br = new BufferedReader(new FileReader("roboherd.in"));
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PrintWriter pw = new PrintWriter(new FileWriter("roboherd.out")));
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StringTokenizer st = new StringTokenizer(br.readLine());
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int N = Integer.parseInt(st.nextToken());
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int K = Integer.parseInt(st.nextToken());
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@ -237,16 +245,17 @@ public class roboherd_buffered_reader_string_tokenizer {
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int M = Integer.parseInt(st.nextToken()); P[i] = new int[M];
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for(int j = 0; j < M; ++j) P[i][j] = Integer.parseInt(st.nextToken());
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}
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if(N == 3) pw.println(61);
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else pw.println(1000000000000000000L);
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pw.close();
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}
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}
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```
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</spoiler>
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*Reading input with `BufferedReader` and `StreamTokenizer`*:
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_Reading input with `BufferedReader` and `StreamTokenizer`_:
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<spoiler title="569ms">
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@ -264,7 +273,7 @@ public class roboherd {
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public static void main(String[] args) throws Exception {
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in = new StreamTokenizer(new BufferedReader(new FileReader("roboherd.in")));
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PrintWriter pw = new PrintWriter(new FileWriter("roboherd.out"));
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int N = nextInt();
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int K = nextInt();
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for(int i = 0; i < N; ++i) {
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@ -291,30 +300,30 @@ import java.io.*;
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//320ms
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public class roboherd_is {
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static int P[][] = new int[100000][];
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public static void main(String[] args) throws Exception {
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FastIO sc = new FastI("roboherd.in");
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PrintWriter pw = new PrintWriter(new FileWriter("roboherd.out"));
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int N = sc.nextInt();
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int K = sc.nextInt();
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for(int i = 0; i < N; ++i) {
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int M = sc.nextInt(); P[i] = new int[M];
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for(int j = 0; j < M; ++j) P[i][j] = sc.nextInt();
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}
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if(N == 3) pw.println(61);
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else pw.println(1000000000000000000L);
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pw.close();
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}
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// new FastI("file_name") to read a file
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// new FastI(System.in) to read from stdin
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// has similar syntax to Scanner, though much faster :)
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static class FastI {
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InputStream dis;
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byte[] buffer = new byte[1 << 17];
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int pointer = 0;
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@ -393,6 +402,7 @@ public class roboherd_is {
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}
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}
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```
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</spoiler>
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The most realistic input method to implement in contest is `BufferedReader`, as it is relatively fast for the amount of code necessary.
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|
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@ -442,4 +452,4 @@ When printing to the standard output stream in Java, it is faster to use `new Pr
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</JavaSection>
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</LanguageSection>
|
||||
</LanguageSection>
|
||||
|
|
@ -1,25 +1,16 @@
|
|||
---
|
||||
id: running-cpp
|
||||
title: Running C++
|
||||
author: Nathan Wang, Benjamin Qi, Anthony Wang
|
||||
description: Options for running C++ both online and locally.
|
||||
---
|
||||
|
||||
Please let us know if these installation instructions do not work for you.
|
||||
|
||||
# Using C++ Online
|
||||
|
||||
- [OnlineGDB](https://www.onlinegdb.com/)
|
||||
- online compiler with an embedded GDB debugger
|
||||
- can be buggy sometimes
|
||||
- supports files and file I/O
|
||||
- [CSAcademy](https://csacademy.com/workspace/)
|
||||
- pretty nice (unless you get "Estimated Queue Time: ...")
|
||||
- "saved locally" will not save your code if you close the tab, press Command-S to save.
|
||||
- [Ideone](http://ideone.com/)
|
||||
- okay ... has the bare minimum you need for running C++
|
||||
- make sure your code is not public (see below)
|
||||
- sometimes erases your code when you first create it (so get in the habit of copying your code first)
|
||||
- [OnlineGDB](https://www.onlinegdb.com/)
|
||||
- online compiler with an embedded GDB debugger
|
||||
- can be buggy sometimes
|
||||
- supports files and file I/O
|
||||
- [CSAcademy](https://csacademy.com/workspace/)
|
||||
- pretty nice (unless you get "Estimated Queue Time: ...")
|
||||
- "saved locally" will not save your code if you close the tab, press Command-S to save.
|
||||
- [Ideone](http://ideone.com/)
|
||||
- okay ... has the bare minimum you need for running C++
|
||||
- make sure your code is not public (see below)
|
||||
- sometimes erases your code when you first create it (so get in the habit of copying your code first)
|
||||
|
||||
<warning-block>
|
||||
|
||||
|
|
@ -36,12 +27,34 @@ You can also share code with [pastebin](https://pastebin.com/) or [hastebin](htt
|
|||
These often have C++ support already built-in.
|
||||
|
||||
<resources>
|
||||
<resource title="Visual Studio Code" url="https://code.visualstudio.com/" starred>Lightweight, fast IDE, but requires some configuration. See <a href="http://www.csc.kth.se/~jsannemo/slask/main.pdf">PAPC 2.1</a> for setup instructions.</resource>
|
||||
<resource title="Geany" url="https://www.geany.org/" starred>Lightweight, frequently used at IOI.</resource>
|
||||
<resource title="Visual Studio" url="https://visualstudio.microsoft.com/vs/">Heavier cousin of VS Code. VS Code is better for competitive programming.</resource>
|
||||
<resource title="Codeblocks" url="http://www.codeblocks.org/">Bad on Mac.</resource>
|
||||
<resource title="XCode" url="https://developer.apple.com/xcode/">Mac only.</resource>
|
||||
<resource title="CLion" url="https://www.jetbrains.com/clion/">Requires a license, but <a href="https://www.jetbrains.com/community/education/#students">free for students</a>.</resource>
|
||||
<resource
|
||||
title="Visual Studio Code"
|
||||
url="https://code.visualstudio.com/"
|
||||
starred
|
||||
>
|
||||
Lightweight, fast IDE, but requires some configuration. See{' '}
|
||||
<a href="http://www.csc.kth.se/~jsannemo/slask/main.pdf">PAPC 2.1</a> for
|
||||
setup instructions.
|
||||
</resource>
|
||||
<resource title="Geany" url="https://www.geany.org/" starred>
|
||||
Lightweight, frequently used at IOI.
|
||||
</resource>
|
||||
<resource title="Visual Studio" url="https://visualstudio.microsoft.com/vs/">
|
||||
Heavier cousin of VS Code. VS Code is better for competitive programming.
|
||||
</resource>
|
||||
<resource title="Codeblocks" url="http://www.codeblocks.org/">
|
||||
Bad on Mac.
|
||||
</resource>
|
||||
<resource title="XCode" url="https://developer.apple.com/xcode/">
|
||||
Mac only.
|
||||
</resource>
|
||||
<resource title="CLion" url="https://www.jetbrains.com/clion/">
|
||||
Requires a license, but{' '}
|
||||
<a href="https://www.jetbrains.com/community/education/#students">
|
||||
free for students
|
||||
</a>
|
||||
.
|
||||
</resource>
|
||||
</resources>
|
||||
|
||||
# Using Command Line
|
||||
|
|
@ -51,22 +64,28 @@ Alternatively, run C++ from the command line and use a text editor of your choic
|
|||
## Text Editors
|
||||
|
||||
<resources>
|
||||
<resource title="Sublime Text 3" url="https://www.sublimetext.com/" starred>Fast, lightweight. Keeps asking you to purchase a license ...</resource>
|
||||
<resource title="Atom" url="https://atom.io/">From the makers of Github.</resource>
|
||||
<resource title="Vim" url="https://www.vim.org/">Classic text editor, usually preinstalled on Linux.</resource>
|
||||
<resource title="Sublime Text 3" url="https://www.sublimetext.com/" starred>
|
||||
Fast, lightweight. Keeps asking you to purchase a license ...
|
||||
</resource>
|
||||
<resource title="Atom" url="https://atom.io/">
|
||||
From the makers of Github.
|
||||
</resource>
|
||||
<resource title="Vim" url="https://www.vim.org/">
|
||||
Classic text editor, usually preinstalled on Linux.
|
||||
</resource>
|
||||
</resources>
|
||||
|
||||
Vim is probably the easiest way to print syntax-highlighted code on Mac, see the response to [this post](https://stackoverflow.com/questions/1656914/printing-code-with-syntax-highlighting).
|
||||
|
||||
### Sublime Text Notes (Ben)
|
||||
|
||||
- I prefer the **Mariana** color scheme in place of the default.
|
||||
- [`subl` symlink](https://www.sublimetext.com/docs/3/osx_command_line.html)
|
||||
- Using `/usr/local/bin/subl` instead of `~/bin/subl` worked for me on OS X Mojave.
|
||||
- [Snippets](https://www.granneman.com/webdev/editors/sublime-text/top-features-of-sublime-text/quickly-insert-text-and-code-with-sublime-text-snippets)
|
||||
- I use [this python script](https://github.com/bqi343/USACO/blob/master/Contests/Tools/Other/makeSnip.py) to update all of my templates. (details?)
|
||||
- [Package - Sublime Linter (GCC)](https://packagecontrol.io/packages/SublimeLinter-gcc)
|
||||
- highlights compilation errors and warnings from `-Wall`
|
||||
- I prefer the **Mariana** color scheme in place of the default.
|
||||
- [`subl` symlink](https://www.sublimetext.com/docs/3/osx_command_line.html)
|
||||
- Using `/usr/local/bin/subl` instead of `~/bin/subl` worked for me on OS X Mojave.
|
||||
- [Snippets](https://www.granneman.com/webdev/editors/sublime-text/top-features-of-sublime-text/quickly-insert-text-and-code-with-sublime-text-snippets)
|
||||
- I use [this python script](https://github.com/bqi343/USACO/blob/master/Contests/Tools/Other/makeSnip.py) to update all of my templates. (details?)
|
||||
- [Package - Sublime Linter (GCC)](https://packagecontrol.io/packages/SublimeLinter-gcc)
|
||||
- highlights compilation errors and warnings from `-Wall`
|
||||
|
||||
<!-- - [FastOlympicCoding Addon](https://github.com/Jatana/FastOlympicCoding)
|
||||
- not that useful
|
||||
|
|
@ -77,6 +96,7 @@ Vim is probably the easiest way to print syntax-highlighted code on Mac, see the
|
|||
- no need to do this if you just use command line to compile & run
|
||||
|
||||
-->
|
||||
|
||||
## On Linux
|
||||
|
||||
GCC is usually preinstalled on most Linux distros. You can check if it is installed with
|
||||
|
|
@ -114,14 +134,24 @@ Nathan Wang: If you want to code in (neo)vim, you can install WSL and code throu
|
|||
|
||||
### Installation
|
||||
|
||||
1. Open the **Terminal** application and familiarize yourself with some basic commands.
|
||||
1. Open the **Terminal** application and familiarize yourself with some basic commands.
|
||||
|
||||
<resources>
|
||||
<resource source="Jim Hoskins" title="Intro to OS X Command Line" url="https://blog.teamtreehouse.com/introduction-to-the-mac-os-x-command-line" starred></resource>
|
||||
<resource source="Rahul Saigal" title="Mac Terminal Cheat Sheet" url="https://www.makeuseof.com/tag/mac-terminal-commands-cheat-sheet/" starred></resource>
|
||||
<resource
|
||||
source="Jim Hoskins"
|
||||
title="Intro to OS X Command Line"
|
||||
url="https://blog.teamtreehouse.com/introduction-to-the-mac-os-x-command-line"
|
||||
starred
|
||||
></resource>
|
||||
<resource
|
||||
source="Rahul Saigal"
|
||||
title="Mac Terminal Cheat Sheet"
|
||||
url="https://www.makeuseof.com/tag/mac-terminal-commands-cheat-sheet/"
|
||||
starred
|
||||
></resource>
|
||||
</resources>
|
||||
|
||||
2. Install XCode command line tools.
|
||||
2. Install XCode command line tools.
|
||||
|
||||
```
|
||||
xcode-select --install
|
||||
|
|
@ -134,9 +164,9 @@ Nathan Wang: If you want to code in (neo)vim, you can install WSL and code throu
|
|||
softwareupdate -i -a # installs all updates
|
||||
```
|
||||
|
||||
3. Install [Homebrew](https://brew.sh/).
|
||||
3. Install [Homebrew](https://brew.sh/).
|
||||
|
||||
4. Install gcc with Homebrew.
|
||||
4. Install gcc with Homebrew.
|
||||
|
||||
```
|
||||
brew install gcc
|
||||
|
|
@ -150,7 +180,7 @@ Nathan Wang: If you want to code in (neo)vim, you can install WSL and code throu
|
|||
|
||||
probably suffices.
|
||||
|
||||
5. You should be able to compile with `g++` or maybe `g++-#`, where # is the version number (ex. 9). Running the following command
|
||||
5. You should be able to compile with `g++` or maybe `g++-#`, where # is the version number (ex. 9). Running the following command
|
||||
|
||||
```
|
||||
g++-9 --version
|
||||
|
|
@ -215,10 +245,10 @@ Use [compiler flags](https://developers.redhat.com/blog/2018/03/21/compiler-and-
|
|||
|
||||
Explanation:
|
||||
|
||||
- `-O2` tells `g++` to compile your code to run more quickly (see [here](https://www.rapidtables.com/code/linux/gcc/gcc-o.html))
|
||||
- `-std=c++17` allows you to use features that were added to C++ in 2017. USACO currently uses `-std=c++11`.
|
||||
- `-Wall -Wextra -Wshadow` checks your program for common errors. See "General - Debugging" for more information.
|
||||
- [Summary of Options](https://gcc.gnu.org/onlinedocs/gcc/Option-Summary.html)
|
||||
- `-O2` tells `g++` to compile your code to run more quickly (see [here](https://www.rapidtables.com/code/linux/gcc/gcc-o.html))
|
||||
- `-std=c++17` allows you to use features that were added to C++ in 2017. USACO currently uses `-std=c++11`.
|
||||
- `-Wall -Wextra -Wshadow` checks your program for common errors. See "General - Debugging" for more information.
|
||||
- [Summary of Options](https://gcc.gnu.org/onlinedocs/gcc/Option-Summary.html)
|
||||
|
||||
You should always compile with these flags.
|
||||
|
||||
1
additionalContent/Running_Java.mdx
Normal file
1
additionalContent/Running_Java.mdx
Normal file
|
|
@ -0,0 +1 @@
|
|||
who cares about java
|
||||
|
|
@ -1,10 +1,3 @@
|
|||
---
|
||||
id: running-python
|
||||
title: Running Python
|
||||
author: Hankai Zhang
|
||||
description: Options for running Python both online and locally.
|
||||
---
|
||||
|
||||
## Running Python Locally
|
||||
|
||||
Download Python through [the official website](https://python.org). On Windows and Mac, you can download executable files directly; on Linux, you must either download the Python source code and compile from source, or obtain Python through your package manager.
|
||||
|
|
@ -1,16 +1,17 @@
|
|||
---
|
||||
id: shorten-cpp
|
||||
title: Shortening C++ Code
|
||||
author: Benjamin Qi
|
||||
description: How to make your code (un?)readable.
|
||||
---
|
||||
|
||||
## Introduction
|
||||
# Shortening C++
|
||||
|
||||
<resources>
|
||||
<resource source="CPH" title="1.4 - Shortening Code" starred>Read before checking code below.</resource>
|
||||
<resource source="GFG" url="cc-preprocessors" title="Macros"></resource>
|
||||
<resource source="GCC" url="https://gcc.gnu.org/onlinedocs/cpp/Macros.html" title="Online Docs - Macros">reference</resource>
|
||||
<resource source="CPH" title="1.4 - Shortening Code" starred>
|
||||
Read before checking code below.
|
||||
</resource>
|
||||
<resource source="GFG" url="cc-preprocessors" title="Macros"></resource>
|
||||
<resource
|
||||
source="GCC"
|
||||
url="https://gcc.gnu.org/onlinedocs/cpp/Macros.html"
|
||||
title="Online Docs - Macros"
|
||||
>
|
||||
reference
|
||||
</resource>
|
||||
</resources>
|
||||
|
||||
## [My Template](https://github.com/bqi343/USACO/blob/master/Implementations/content/contest/template.cpp)
|
||||
|
|
@ -32,7 +33,7 @@ Pretty annoying to keep typing `first` and `second` (especially if you have nest
|
|||
### Vectors
|
||||
|
||||
```cpp
|
||||
typedef vector<int> vi;
|
||||
typedef vector<int> vi;
|
||||
|
||||
#define sz(x) (int)x.size()
|
||||
#define all(x) begin(x), end(x)
|
||||
|
|
@ -41,7 +42,7 @@ typedef vector<int> vi;
|
|||
It's generally a good idea to convert a size to a signed integer before doing anything with it to avoid cases like the following.
|
||||
|
||||
```cpp
|
||||
vi x;
|
||||
vi x;
|
||||
cout << x.size()-1 << "\n"; // 18446744073709551615
|
||||
cout << sz(x)-1 << "\n"; // -1
|
||||
```
|
||||
|
|
@ -63,7 +64,7 @@ const ll INF = 1e18;
|
|||
const ld PI = acos((ld)-1);
|
||||
```
|
||||
|
||||
$10^9+7$ is a prime that appears quite frequently in programming contests. Interestingly, $(10^9+7-1)/2=5\cdot 10^8+3$ is also prime. On the other hand, $998244353-1$ is divisible by $2^{23}$, which is useful for [NTT](https://en.wikipedia.org/wiki/Discrete_Fourier_transform_(general)#Number-theoretic_transform).
|
||||
$10^9+7$ is a prime that appears quite frequently in programming contests. Interestingly, $(10^9+7-1)/2=5\cdot 10^8+3$ is also prime. On the other hand, $998244353-1$ is divisible by $2^{23}$, which is useful for [NTT](<https://en.wikipedia.org/wiki/Discrete_Fourier_transform_(general)#Number-theoretic_transform>).
|
||||
|
||||
Almost all USACO problems satisfy $N\le 2\cdot 10^5$, so that's what `MX` is for.
|
||||
|
||||
|
|
@ -78,18 +79,24 @@ See [neal's blog](https://codeforces.com/blog/entry/61587) about why `rand()` is
|
|||
### Template
|
||||
|
||||
```cpp
|
||||
template<class T> bool ckmin(T& a, const T& b) {
|
||||
template<class T> bool ckmin(T& a, const T& b) {
|
||||
return b < a ? a = b, 1 : 0; }
|
||||
template<class T> bool ckmax(T& a, const T& b) {
|
||||
return a < b ? a = b, 1 : 0; }
|
||||
```
|
||||
|
||||
See [negCyc](https://github.com/bqi343/USACO/blob/master/Implementations/content/graphs%20(12)/Basics/NegativeCycle%20(7.3).h) for an example of usage.
|
||||
See [negCyc](<https://github.com/bqi343/USACO/blob/master/Implementations/content/graphs%20(12)/Basics/NegativeCycle%20(7.3).h>) for an example of usage.
|
||||
|
||||
### Lambda Expressions
|
||||
|
||||
<resources>
|
||||
<resource source="GFG" url="lambda-expression-in-c" title = "Lambda Expressions in C++"> </resource>
|
||||
<resource
|
||||
source="GFG"
|
||||
url="lambda-expression-in-c"
|
||||
title="Lambda Expressions in C++"
|
||||
>
|
||||
{' '}
|
||||
</resource>
|
||||
</resources>
|
||||
|
||||
(describe more)
|
||||
(describe more)
|
||||
|
|
@ -1,6 +1,6 @@
|
|||
---
|
||||
id: contest-strategy
|
||||
title: Contest Strategy
|
||||
title: (Optional) Contest Strategy
|
||||
author: Nathan Chen
|
||||
description: General ideas on how to strategize during a USACO contest.
|
||||
---
|
||||
|
|
@ -72,7 +72,7 @@ You do not need to learn pointers (for now). Knowledge of structs and classes is
|
|||
|
||||
</info-block>
|
||||
|
||||
## Resources for Getting Started
|
||||
## Additional Resources
|
||||
|
||||
<resources title="Getting Started">
|
||||
<resource source="CodeSignal" title="CodeSignal" url="https://codesignal.com/" starred>can practice basics with "Arcade," "Interview Practice"</resource>
|
||||
|
|
|
|||
|
|
@ -1,6 +1,6 @@
|
|||
---
|
||||
id: practicing
|
||||
title: How to Practice
|
||||
title: (Optional) How to Practice
|
||||
author: Many
|
||||
description: How to practice and when to read editorials (analyses) according to various USACO competitors.
|
||||
---
|
||||
34
content/1_Intro/Running_Code.mdx
Normal file
34
content/1_Intro/Running_Code.mdx
Normal file
|
|
@ -0,0 +1,34 @@
|
|||
---
|
||||
id: running-code
|
||||
title: Running Code
|
||||
author: Benjamin Qi, Hankai Zhang, Anthony Wang, Nathan Wang
|
||||
description: Options for running your language of choice.
|
||||
---
|
||||
|
||||
import RunningCpp from "../../additionalContent/Running_Cpp.mdx";
|
||||
import RunningJava from "../../additionalContent/Running_Java.mdx";
|
||||
import RunningPython from "../../additionalContent/Running_Python.mdx";
|
||||
|
||||
Please let us know if these installation instructions do not work for you.
|
||||
|
||||
<LanguageSection>
|
||||
|
||||
<CPPSection>
|
||||
|
||||
<RunningCpp />
|
||||
|
||||
</CPPSection>
|
||||
|
||||
<JavaSection>
|
||||
|
||||
<RunningJava />
|
||||
|
||||
</JavaSection>
|
||||
|
||||
<PySection>
|
||||
|
||||
<RunningPython />
|
||||
|
||||
</PySection>
|
||||
|
||||
</LanguageSection>
|
||||
|
|
@ -1,8 +0,0 @@
|
|||
---
|
||||
id: running-java
|
||||
title: Running Java
|
||||
author: ?
|
||||
description: Options for running Java both online and locally.
|
||||
---
|
||||
|
||||
who cares about java
|
||||
26
content/1_Intro/Tips_Tricks.mdx
Normal file
26
content/1_Intro/Tips_Tricks.mdx
Normal file
|
|
@ -0,0 +1,26 @@
|
|||
---
|
||||
id: tips-tricks
|
||||
title: Tips & Tricks
|
||||
author: Benjamin Qi, Nathan Chen, Aaron Chew, Nathan Wang
|
||||
description: "Tips & tricks that will help you code better and faster: I/O speed, Debugging, & Macros."
|
||||
---
|
||||
|
||||
import InputOutput from "../../additionalcontent/Input_Output.mdx";
|
||||
import DebuggingCpp from "../../additionalContent/Debugging_Cpp.mdx";
|
||||
import ShortenCpp from "../../additionalContent/Shorten_Cpp.mdx";
|
||||
|
||||
<InputOutput />
|
||||
|
||||
<LanguageSection>
|
||||
|
||||
<CPPSection>
|
||||
|
||||
<DebuggingCpp />
|
||||
<ShortenCpp />
|
||||
|
||||
</CPPSection>
|
||||
|
||||
<JavaSection />
|
||||
<PythonSection />
|
||||
|
||||
</LanguageSection>
|
||||
|
|
@ -11,10 +11,6 @@ Skipping around is especially recommended for higher level contestants (Gold/Pla
|
|||
|
||||
For lower level contestants, the guide is generally designed to be completed in order. There are some exceptions; for example, the last module in "Silver -> Sorting" assumes knowledge of the first two modules in "Silver -> Ordered Sets & Maps." In any case, we will list **prerequisites** to each module as needed.
|
||||
|
||||
## The General Section
|
||||
|
||||
The following _section_ (not module!) "General" will contain a list of modules not specific to any division. We recommend you read through the ones you find interesting, but **skip the ones that aren't relevant to you!**<Asterisk>However, it's a good idea to read them all eventually :)</Asterisk> This is especially true for those just getting started with Competitive Programming.
|
||||
|
||||
## Features of this Guide
|
||||
|
||||
As you use this guide, here are some features that you may find helpful:
|
||||
|
|
|
|||
|
|
@ -1,227 +0,0 @@
|
|||
---
|
||||
id: why-cpp
|
||||
title: Why C++?
|
||||
author: Benjamin Qi
|
||||
description: Some reasons why choice of language matters significantly outside of USACO Bronze.
|
||||
---
|
||||
|
||||
## Time Limit
|
||||
|
||||
Although both Python and Java receive two times the C++ time limit in USACO, this is not the case for most other websites (ex. CodeForces). Even with the extended time limits, Python and Java sometimes have trouble passing.
|
||||
|
||||
- Rewriting the C++ solution for [USACO Silver Wormsort](http://www.usaco.org/index.php?page=viewproblem2&cpid=992) in Python receives TLE (Time Limit Exceeded) on 2/10 cases. I'm not sure whether it is possible to pass this problem with Python.
|
||||
|
||||
<spoiler title="Python3 8/10 Solution">
|
||||
|
||||
```py
|
||||
# 8/10 test cases ...
|
||||
|
||||
fin = open("wormsort.in","r")
|
||||
lines = [line for line in fin]
|
||||
N,M = map(int,lines[0].split())
|
||||
p = list(map(lambda x: int(x)-1,lines[1].split()))
|
||||
|
||||
ed = []
|
||||
for i in range(2,len(lines)):
|
||||
a,b,w = map(int,lines[i].split())
|
||||
a -= 1
|
||||
b -= 1
|
||||
ed.append([w,a,b])
|
||||
ed.sort()
|
||||
ed.reverse()
|
||||
|
||||
adj = [[] for i in range(N)]
|
||||
vis = [0 for i in range(N)]
|
||||
cnt = 0
|
||||
|
||||
def dfs(x):
|
||||
global cnt
|
||||
if vis[x] != 0:
|
||||
return
|
||||
vis[x] = cnt
|
||||
for i in adj[x]:
|
||||
dfs(i)
|
||||
|
||||
def ok(mid):
|
||||
global cnt
|
||||
for i in range(N):
|
||||
vis[i] = 0
|
||||
adj[i].clear()
|
||||
for i in range(mid):
|
||||
a,b = ed[i][1],ed[i][2]
|
||||
adj[a].append(b)
|
||||
adj[b].append(a)
|
||||
for i in range(N):
|
||||
if vis[i] == 0:
|
||||
cnt += 1
|
||||
todo = [i]
|
||||
ind = 0
|
||||
while ind < len(todo):
|
||||
x = todo[ind]
|
||||
ind += 1
|
||||
vis[x] = cnt
|
||||
for i in adj[x]:
|
||||
if vis[i] == 0:
|
||||
vis[i] = -cnt
|
||||
todo.append(i)
|
||||
ok = True
|
||||
for i in range(N):
|
||||
if vis[i] != vis[p[i]]:
|
||||
ok = False
|
||||
return ok
|
||||
|
||||
lo,hi = 0,M
|
||||
while lo < hi:
|
||||
mid = (lo+hi)//2
|
||||
if ok(mid):
|
||||
hi = mid
|
||||
else:
|
||||
lo = mid+1
|
||||
|
||||
fout = open("wormsort.out","w")
|
||||
|
||||
fout.write(str(-1 if lo == 0 else ed[lo-1][0]))
|
||||
fout.write('\n')
|
||||
```
|
||||
|
||||
</spoiler>
|
||||
|
||||
- A similar solution in Java requires almost 3s, which is fairly close to the time limit of 4s.
|
||||
|
||||
<spoiler title="Java Solution">
|
||||
|
||||
```java
|
||||
import java.io.*; // from Nick Wu
|
||||
import java.util.*;
|
||||
public class wormsort {
|
||||
public static void main(String[] args) throws IOException{
|
||||
BufferedReader br = new BufferedReader(new FileReader("wormsort.in"));
|
||||
StringTokenizer st = new StringTokenizer(br.readLine());
|
||||
int n = Integer.parseInt(st.nextToken());
|
||||
int m = Integer.parseInt(st.nextToken());
|
||||
loc = new int[n];
|
||||
component = new int[n];
|
||||
edges = new LinkedList[n];
|
||||
for(int i = 0; i < n; i++) edges[i] = new LinkedList<>();
|
||||
lhs = new int[m];
|
||||
rhs = new int[m];
|
||||
weight = new int[m];
|
||||
st = new StringTokenizer(br.readLine());
|
||||
for(int i = 0; i < n; i++) loc[i] = Integer.parseInt(st.nextToken())-1;
|
||||
for(int i = 0; i < m; i++) {
|
||||
st = new StringTokenizer(br.readLine());
|
||||
lhs[i] = Integer.parseInt(st.nextToken())-1;
|
||||
rhs[i] = Integer.parseInt(st.nextToken())-1;
|
||||
weight[i] = Integer.parseInt(st.nextToken());
|
||||
}
|
||||
br.close();
|
||||
int minW = 0;
|
||||
int maxW = 1000000001;
|
||||
while(minW != maxW) {
|
||||
int mid = (minW + maxW + 1) / 2;
|
||||
if(valid(mid)) minW = mid;
|
||||
else maxW = mid-1;
|
||||
}
|
||||
if(minW > 1e9) minW = -1;
|
||||
PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter("wormsort.out")));
|
||||
pw.println(minW);
|
||||
pw.close();
|
||||
}
|
||||
static int[] loc, lhs, rhs, weight;
|
||||
static LinkedList<Integer>[] edges;
|
||||
static int[] component;
|
||||
private static void dfs(int curr, int label) {
|
||||
if(component[curr] == label) return;
|
||||
component[curr] = label;
|
||||
for(int child: edges[curr]) dfs(child, label);
|
||||
}
|
||||
private static boolean valid(int minW) {
|
||||
Arrays.fill(component, -1);
|
||||
for(int i = 0; i < edges.length; i++) edges[i].clear();
|
||||
for(int i = 0; i < lhs.length; i++) {
|
||||
if(weight[i] >= minW) {
|
||||
edges[lhs[i]].add(rhs[i]);
|
||||
edges[rhs[i]].add(lhs[i]);
|
||||
}
|
||||
}
|
||||
int numcomps = 0;
|
||||
for(int i = 0; i < component.length; i++) {
|
||||
if(component[i] < 0) {
|
||||
dfs(i, numcomps++);
|
||||
}
|
||||
}
|
||||
for(int i = 0; i < loc.length; i++) {
|
||||
if(component[i] != component[loc[i]]) return false;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
</spoiler>
|
||||
|
||||
- A comparable C++ solution runs in less than 700ms.
|
||||
|
||||
<spoiler title="C++ Solution">
|
||||
|
||||
```cpp
|
||||
#include <bits/stdc++.h>
|
||||
using namespace std;
|
||||
|
||||
typedef vector<int> vi;
|
||||
|
||||
const int MX = 1e5+5;
|
||||
|
||||
int loc[MX], comp[MX], lhs[MX], rhs[MX], wei[MX];
|
||||
vi adj[MX];
|
||||
int n,m;
|
||||
|
||||
void dfs(int cur, int label) {
|
||||
if (comp[cur] == label) return;
|
||||
comp[cur] = label;
|
||||
for (int c: adj[cur]) dfs(c,label);
|
||||
}
|
||||
|
||||
bool valid(int minW) {
|
||||
for (int i = 0; i < n; ++i) {
|
||||
comp[i] = -1;
|
||||
adj[i].clear();
|
||||
}
|
||||
for (int i = 0; i < m; ++i) if (wei[i] >= minW)
|
||||
adj[lhs[i]].push_back(rhs[i]), adj[rhs[i]].push_back(lhs[i]);
|
||||
int numComps = 0;
|
||||
for (int i = 0; i < n; ++i) if (comp[i] < 0)
|
||||
dfs(i,numComps++);
|
||||
for (int i = 0; i < n; ++i)
|
||||
if (comp[i] != comp[loc[i]]) return 0;
|
||||
return 1;
|
||||
}
|
||||
|
||||
int main() {
|
||||
ios_base::sync_with_stdio(0); cin.tie(0);
|
||||
freopen("wormsort.in","r",stdin);
|
||||
freopen("wormsort.out","w",stdout);
|
||||
cin >> n >> m;
|
||||
for (int i = 0; i < n; ++i) cin >> loc[i], loc[i] --;
|
||||
for (int i = 0; i < m; ++i) {
|
||||
cin >> lhs[i], lhs[i] --;
|
||||
cin >> rhs[i], rhs[i] --;
|
||||
cin >> wei[i];
|
||||
}
|
||||
int minW = 0, maxW = (int)1e9+1;
|
||||
while (minW != maxW) {
|
||||
int mid = (minW+maxW+1)/2;
|
||||
if (valid(mid)) minW = mid;
|
||||
else maxW = mid-1;
|
||||
}
|
||||
if (minW > 1e9) minW = -1;
|
||||
cout << minW;
|
||||
}
|
||||
```
|
||||
</spoiler>
|
||||
|
||||
## Other Notes
|
||||
|
||||
- USACO problemsetters don't always test Java (and rarely Python) solutions when setting constraints.
|
||||
- Python lacks a data structure that keeps its keys in sorted order (the equivalent of `set` in C++), which is required for some silver problems.
|
||||
- Java lacks features such as `#define`, `typedef`, and `auto` that are present in C++ (which some contestants rely on extensively, see "macros").
|
||||
|
|
@ -14,27 +14,20 @@ const ModuleOrdering: {[key: string]: ModuleOrderingItem[]} = {
|
|||
name: "Languages",
|
||||
items: [
|
||||
"lang",
|
||||
"running-cpp",
|
||||
"running-java",
|
||||
"running-python",
|
||||
"running-code",
|
||||
"tips-tricks",
|
||||
]
|
||||
},
|
||||
"data-types",
|
||||
"io",
|
||||
],
|
||||
"general": [
|
||||
"resources",
|
||||
"practicing",
|
||||
"contests",
|
||||
"contest-strategy",
|
||||
"proposing",
|
||||
{
|
||||
name: "Language-Specific",
|
||||
name: "Other",
|
||||
items: [
|
||||
"io-speed",
|
||||
"why-cpp",
|
||||
"shorten-cpp",
|
||||
"debugging",
|
||||
"resources",
|
||||
"contests",
|
||||
"proposing",
|
||||
]
|
||||
},
|
||||
],
|
||||
|
|
|
|||
|
|
@ -196,7 +196,7 @@ export default function Template(props) {
|
|||
{/* End Hero Section */}
|
||||
|
||||
<div className="pb-8" id="content">
|
||||
<div className="max-w-4xl mx-auto px-4 sm:px-6 lg:px-8 pb-4">
|
||||
<div className="max-w-3xl mx-auto px-4 sm:px-6 lg:px-8 pb-4">
|
||||
<div
|
||||
className="mb-8 bg-white shadow-md rounded-lg relative"
|
||||
style={{ marginTop: '-12rem' }}
|
||||
|
|
@ -237,7 +237,7 @@ export default function Template(props) {
|
|||
</nav>
|
||||
</div>
|
||||
|
||||
<ol className="list-inside py-8 px-8 text-lg space-y-1">
|
||||
<ol className="list-inside p-4 sm:p-8 text-lg space-y-1">
|
||||
{module.map((m, idx) => {
|
||||
if (m.hasOwnProperty('items')) {
|
||||
return (
|
||||
|
|
|
|||
Reference in a new issue