CHi simmetria ili ne chi

#include <iostream>
#include <vector>
#include <cmath>
using namespace std;
bool IsSymmetric(vector<vector<int>> a)
{
    int n,k,i,j;
    n=a.size();
    k=1;
    for (i=0;i<n;++i){
        for (j=0;j<n;++j){
            if (a[i][j]==a[j][i])
                k+=1;
            else{
                k=-112;
                break;}
        }
        if (k<0)
            break;
    }
    return (k>0);
}
int main()
{
    int n,i,j;
    cin >> n;
    vector < vector<int>> a(n, vector<int>(n));
    for(i=0;i<n;++i)
    {
        for(j=0;j<n;++j)
            cin >> a[i][j];
    }
    if (IsSymmetric(a))
        cout<<"yes";
    else
        cout<<"no";
    return 0;
}