#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], ml = -1; int send_message(int N, int i, int Pi){ p[i] = Pi; if(i >= N - 7){ 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 mx = 1; for(int j = 2; j <= N; j++) if(v[j] > v[mx]) mx = j; if(i == N - 1 && mx != ml) return 4; ml = mx; int tmp = mx; for(int d = 6; d >= 0; --d){ vt[d] = tmp % 4; tmp /= 4; } return vt[i - (N - 7)]; } return 0; } pair<int,int> longest_path(vector<int> S){ int mx = 0; for(int i = S.size() - 7; i < S.size(); i++){ if(S[i] == 4) return {0, i}; mx = mx * 4 + S[i]; } return {0, mx}; }