/***********************************************
* auth: tapilyoca *
* date: 02/16/2025 at 20:02:38 *
* dots: https://github.com/tapilyoca/dotilyoca *
***********************************************/
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector<ll>;
/***********************************************/
void DFS(int curr, vector<bool> &vis, unordered_set<int> &wait, vector<vector<int>> adj){
if(vis[curr]){
return;
}
vis[curr] = 1;
wait.insert(curr);
if(adj[curr].size() == 0){
return;
}
for(int c : adj[curr]){
DFS(c, vis, wait, adj);
}
}
int solve(int N, int M, vector<int> F, vector<vector<int>> S){
vector<vector<int>> kids(N+1);
for(int i = 1; i < N; i++){
kids[F[i]].push_back(i);
}
vector<bool> vis(N+1, 0);
unordered_set<int> waiting;
vector<int> freq(N,0);
int ans = 0;
for(int i = 0; i < N-1; i++){
for(int j = 0; j < M; j++){
int at = S[j][i];
waiting.insert(at);
freq[at]++;
if(!vis[at]){
// then we haven't touched this yet
// so set all of the children to be visited
DFS(at,vis,waiting,kids);
}
vis[at] = 1;
if(freq[at] == M){
// cerr << "ERASING" << endl;
waiting.erase(at);
}
}
// waiting
// cout << "WAITING ON " << i << " : " << endl;
// for(auto itr = waiting.begin(); itr != waiting.end(); itr++){
// cout << *itr << " ";
// }
if(waiting.size() == 0){
ans++;
}
}
return ans;
}
