题解 | 对称矩阵

#include <iostream>
#include <vector>

using namespace std;

int main() 
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int N;
    while(cin >> N)
    {
        vector<vector<int>> vec(N, vector<int>(N));
        for(int i = 0; i < N; i++)
        {
            for(int j = 0; j < N; j++) cin >> vec[i][j];
        }
        int is = 1;
        for(int i = 1; i < N; i++)
        {
            for(int j = 0; j < i; j++)
            {
                if(vec[i][j] != vec[j][i]) is = 0;
            }
        }
        if(is == 1) cout << "Yes!" << "\n";
        else cout << "No!" << "\n";
    }
    return 0;
}