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OI-codes/Codeforces/402/E/E.cpp

45 lines
693 B
C++

#include <iostream>
#include <bitset>
using std::cin;
using std::cout;
const char endl = '\n';
const int N = 2005;
int n;
std::bitset<N> g[N];
int main() {
std::ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n;
for (int i = 1; i <= n; i++) {
for (int j = 1, x; j <= n; j++) {
cin >> x;
g[i][j] = x;
}
}
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
if (g[j][i]) g[j] |= g[i];
}
}
for (int i = 1; i <= n; i++) {
if (g[i].count() != n) {
cout << "NO" << endl;
exit(0);
}
}
cout << "YES" << endl;
return 0;
}