Submission #1982921

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Source Code Expand

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

const int inf = 1001001001;

int main() {
  int t;
  cin >> t;

  while (t--) {
    int n;
    cin >> n;
    vector<vector<int>> d(n, vector<int>(n, 0));
    for (int i = 0; i < n; ++i) {
      for (int j = 0; j < n; ++j) {
        cin >> d[i][j];
        if (d[i][j] == -1) d[i][j] = inf;
      }
    }

    bool izryt = true;
    for (int k = 0; k < n; ++k) {
      for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
          if (d[i][j] > d[i][k] + d[k][j]) izryt = false;
        }
      }
    }

    for (int i = 0; i < n; ++i) {
      if (d[i][i]) izryt = false;
    }

    cout << (izryt ? "YES" : "NO") << endl;
  }
}

Submission Info

Judge Result