#include <bits/stdc++.h> using namespace std; int p[10001]; vector<vector<int>> a; vector<int> v; void dfs(int u, int k, int cnt){ v[u] = cnt; for(int e : a[u]) if(e != k) dfs(e, u, cnt + 1); } int vt[7]; pair<int,int> ml = {-1,-1}; int send_message(int N, int i, int Pi){ p[i] = Pi; if(i >= N - 2){ a.assign(N + 1, {}); v.assign(N + 1, 0); for(int j = 1; j <= N; j++) a[p[j]].push_back(j); dfs(0, -1, 0);int u = 0; for(int j = 0; j <= N; j++) if(v[j] > v[u]) u = j; dfs(u, -1, 0);int vtx = u; for(int j = 0; j <= N; j++) if(v[j] > v[vtx]) vtx = j; int x = u, y = vtx;if(x > y) swap(x, y); int kp = 0; if(i == N - 1 && ml.first != -1 && make_pair(x, y) != ml) return 10000+x; if(i == N-2) return x; return y; } return 0; } pair<int,int> longest_path(vector<int> S){ if(S[S.size()-1] >= 10000)return {S[S.size()-1]-10000, S.size()-1}; return {S[S.size()-2], S[S.size()-1]}; }