a/Library
1
0
Fork 0
Code Issues Pull requests Packages Projects Releases Wiki Activity

Update fenwick_tree_2d.cpp

Browse source
This commit is contained in:
Anthony Wang 2020-06-26 11:51:11 -05:00
parent d9d672e7ae
commit 28aa8c28f6
1 changed files with 6 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

12
Data Structures/fenwick_tree_2d.cpp
View file

@ -1,24 +1,24 @@
class fenwick_tree_2d { template<typename T> class fenwick_tree_2d {
private: int N, M; vector<vector<int>> FT; private: int N, M; vector<vector<T>> FT;
public: public:
fenwick_tree_2d(int n, int m) { fenwick_tree_2d(int n, int m) {
N = n + 1, M = m + 1; N = n + 1, M = m + 1;
FT.resize(N); FT.resize(N);
for (int i = 0; i < N; i++) FT[i].resize(M, 0); for (int i = 0; i < N; i++) FT[i].resize(M, 0);
} }
void update(int x, int y, int val) { void update(int x, int y, T val) {
for (int i = x; i < N; i += i & -i) { for (int i = x; i < N; i += i & -i) {
for (int j = y; j < M; j += j & -j) FT[i][j] += val; for (int j = y; j < M; j += j & -j) FT[i][j] += val;
} }
} }
int query(int x, int y) { T query(int x, int y) {
int ret = 0; T ret = 0;
for (int i = x; i > 0; i -= i & -i) { for (int i = x; i > 0; i -= i & -i) {
for (int j = y; j > 0; j -= j & -j) ret += FT[i][j]; for (int j = y; j > 0; j -= j & -j) ret += FT[i][j];
} }
return ret; return ret;
} }
int query(int xl, int xr, int yl, int yr) { T query(int xl, int xr, int yl, int yr) {
return query(xr, yr) - query(xl - 1, yr) - query(xr, yl - 1) + query(xl - 1, yl - 1); return query(xr, yr) - query(xl - 1, yr) - query(xr, yl - 1) + query(xl - 1, yl - 1);
} }
}; };