APIO 2014 - Beads and Wires

Code

1#include <bits/stdc++.h>
2typedef long long ll;
3using namespace std;
4
5int n, a, b;
6ll w, pw[200001], dp[200001][2][2];
7vector<pair<int, ll>> graph[200001];
8
9void dfs(int node, int par) {
10    if (graph[node].size() == 1 && par != -1) return;