---
slug: /plat/trees
title: "Platinum - Trees"
author: Benjamin Qi
---

# Platinum - Trees

## Tree Diameter

### Tutorial

 - CPH 14.2

### Problems

 - [USACO Plat Newbarns](http://www.usaco.org/index.php?page=viewproblem2&cpid=817)
   - Copy of [Brain Network "Hard"](https://codeforces.com/contest/690/problem/C3)

## Lowest Common Ancestor

### Tutorial

 - CPH 18
 - [cp-algorithms: Lowest Common Ancestor](https://cp-algorithms.com/)

### Problems

 - [USACO Plat Max Flow](http://www.usaco.org/index.php?page=viewproblem2&cpid=576)
 - [USACO Gold Milk Visits](http://www.usaco.org/index.php?page=viewproblem2&cpid=970)
 - [USACO Gold Cow Land](http://www.usaco.org/index.php?page=viewproblem2&cpid=921)
   - LCA + BIT
 - [USACO Plat Promote](http://www.usaco.org/index.php?page=viewproblem2&cpid=696)
   - Subtree + BIT
 - [USACO Plat Disrupt](http://www.usaco.org/index.php?page=viewproblem2&cpid=842)
   - HLD is possible, but just do binary jumps
 - [USACO Plat Tree Boxes](http://www.usaco.org/index.php?page=viewproblem2&cpid=948)
   - interactive!!
 - [USACO Plat Gathering](http://www.usaco.org/index.php?page=viewproblem2&cpid=866)
 - [USACO Plat Exercise](http://www.usaco.org/index.php?page=viewproblem2&cpid=901)
   - tricky

## Centroid Decomposition

 - [USACO Plat - At Large](http://www.usaco.org/index.php?page=viewproblem2&cpid=793)
   - very tricky
 - [DMOJ Bob Equilibrium](https://dmoj.ca/problem/dmopc19c7p6)

## Heavy-Light Decomposition