Submission #3825927

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Source Code Expand

#include <algorithm>
#include <bitset>
#include <cctype>
#include <chrono>
#include <cmath>
#include <cstdio>
#include <ctime>
#include <deque>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <string>
#include <tuple>
#include <unordered_map>
#include <vector>
using namespace std;

#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3fLL;
/*----------------------------------------*/

int main() {
  cin.tie(0); ios::sync_with_stdio(false);
  // freopen("input.txt", "r", stdin);

  int t; cin >> t;
  REP(repeat, t) {
    int n; cin >> n;
    vector<vector<int> > a(n, vector<int>(n));
    bool ok = true;
    REP(i, n) REP(j, n) {
      cin >> a[i][j];
      if (i == j && a[i][j] != 0) ok = false;
    }
    REP(i, n) REP(j, n) {
      if (i == j) continue;
      vector<int> dist(n, INF);
      dist[i] = 0;
      priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>> > que;
      REP(k, n) if (k != i && k != j && a[i][k] != -1) {
        dist[k] = a[i][k];
        que.push(make_pair(dist[k], k));
      }
      while (!que.empty()) {
        auto aut = que.top(); que.pop();
        if (aut.second == j) break;
        if (aut.first != dist[aut.second]) continue;
        REP(k, n) {
          if (a[aut.second][k] != -1 && dist[k] > aut.first + a[aut.second][k]) {
            dist[k] = aut.first + a[aut.second][k];
            que.push(make_pair(dist[k], k));
          }
        }
      }
      if (a[i][j] > dist[j]) {
        ok = false;
        break;
      }
    }
    cout << (ok? "YES" : "NO") << '\n';
  }
  return 0;
}

Submission Info

Judge Result