反向图 + dfs

#include <cstdlib>
#include <iostream>
#include <vector>
using namespace std;

const int N = 110;
int n, m;

vector<int> p(N);
vector<int> t(N);
vector<vector<int>> graph(N);
vector<int> earliest(N, -1);
vector<int> latest(N, -1);

int get_earliest(int i) {
  if (earliest[i] != -1) return earliest[i];
  if (p[i] == 0) return earliest[i] = 1;
  return earliest[i] = get_earliest(p[i]) + t[p[i]];
}

int get_latest(int i) {
  if (latest[i] != -1) return latest[i];
  int max_chain{0};
  for (int j : graph[i]) {
    max_chain = max(max_chain, get_latest(j) + t[j]);
  }
  return latest[i] = max_chain;
}
int main(int argc, char *argv[]) {
  cin >> n >> m;
  for (int i = 1; i <= m; i++) cin >> p[i];
  for (int i = 1; i <= m; i++) cin >> t[i];
  for (int i = 1; i <= m; i++) {
    if (p[i]) graph[p[i]].push_back(i);  // project i rely on project p[i]
  }

  bool can_finish{true};
  for (int i = 1; i <= m; i++) {
    int start_time = get_earliest(i);
    cout << start_time << " ";
    if (can_finish && start_time + t[i] - 1 > n) can_finish = false;
  }
  if (can_finish) {
    cout << endl;
    for (int i = 1; i <= m; i++) {
      cout << n - get_latest(i) - t[i] + 1 << " ";
    }
    cout << endl;
  }

  return 0;
}