#include<bits/stdc++.h> using namespace std; #define pb push_back int p[10001]; int send_message(int N, int i, int Pi) { p[i] = Pi; if (i == N) { vector<vector<int>> graph(10001); for (int i = N; i >= 1; i--) graph[p[i]].pb(i); vector<int> depth(10001, 0); auto dfs = [&](auto &dfs, int u, int p, int dep = 0) -> void { depth[u] = dep; for (int e : graph[u]) if (e != p) dfs(dfs, e, u, dep+1); }; dfs(dfs, 0, 0); int mx = 1; for (int i = 2; i <= N; i++) { if (depth[i] > depth[mx]) mx = i; } return mx; } return 0; } pair<int, int> longest_path(vector<int> S) { return make_pair(0, S.back()); }