题解

#include <bits/stdc++.h>
 
using namespace std;
 
int main() {
  int n;
  cin >> n;
  vector<int> have(n);
  for(auto& x: have) cin >> x;
  int k;
  cin >> k;
  vector<vector<int>> need(n);
  while(k--) {
    int want, m;
    cin >> want >> m;
    need[--want].resize(m);
    for(auto& x: need[want]) {
      cin >> x;
      x--;
    }
  }
  int ret = 0;
  while(true) {
    vector<int> consume(n);
    consume[n-1]++;
    bool good = true;
    for(int i = n-1; i >= 0; i--) {
      if(consume[i] <= have[i]) {
        have[i] -= consume[i];
        continue;
      }
      if(need[i].size() == 0) {
        good = false;
        break;
      }
      int take = min(consume[i], have[i]);
      consume[i] -= take;
      have[i] -= take;
      for(int out: need[i]) consume[out] += consume[i];
    }
    if(good) ret++;
    else break;
  }
  cout << ret << "\n";
}