#include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> typedef long long ll; using namespace __gnu_pbds; using namespace std; template <typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; int n,kk,ans,inf=1e7; int M = 200'010; vector<vector<pair<int, int>>> g(M); void dfs(int v, int p, int d, int c) { if(c==kk) ans = min(ans,d); for(auto[u,k] : g[v]) { if(u==p) continue; dfs(u,v,d+1,c+k); } } int best_path(int N, int K, int H[][2], int L[]) { n=N; kk=K; for(ll i=0; i<n-1; ++i) { ll a = H[i][0]; ll b = H[i][1]; ll c = L[i]; g[a].push_back({b,c}); g[b].push_back({a,c}); } for(int i=0; i<n; ++i) { dfs(i,-1, 0,0); } if(ans==inf) return -1; return ans; }