Submission #857765

#	Time	Username	Problem	Language	Result	Execution time	Memory
857765		qrno	Bosses (BOI16_bosses)	C++14	100 / 100	402 ms	1012 KiB

bosses

#include <bits/stdc++.h>
using namespace std;

const int MAXN = 5e3;

int best = -1;

int N;
array<vector<int>, MAXN> G;
array<int, MAXN> val, last;

int bfs(int s) {
  queue<int> Q;
  val[s] = 1;
  last[s] = s;
  Q.push(s);

  int done = 0, sum = 0;
  while (!Q.empty()) {
    auto v = Q.front(); Q.pop();
    sum += val[v];
    if (best != -1 && sum >= best) return -1;
    done++;
    for (auto u : G[v]) {
      if (last[u] != s) {
        val[u] = val[v]+1;
        last[u] = s;
        Q.push(u);
      }
    }
  }

  if (done < N) return -1;
  return sum;
}

signed main() {
  ios::sync_with_stdio(false); cin.tie(nullptr);

  cin >> N;
  for (int i = 0; i < N; i++) {
    int K; cin >> K;
    while (K--) {
      int u; cin >> u; u--;
      G[u].push_back(i);
    }
  }

  for (int i = 0; i < N; i++) {
    int sum = bfs(i);
    if (sum != -1 && (best == -1 || best > sum))
      best = sum;
  }
  cout << best << endl;
}

• Subtask 1: 22 / 22
• Subtask 2: 45 / 45
• Subtask 3: 33 / 33