Codeforces Round #644 (Div. 3) 1360E - Polygon Solution

 Problem Link: https://codeforces.com/problemset/problem/1360/E

Solution in C++:

///La ilaha illellahu muhammadur rasulullah

///******Bismillahir-Rahmanir-Rahim******///

///Abul Hasnat  Tonmoy

///Department of CSE,23rd batch

///Islamic University,Bangladesh

///**********ALLAH IS ALMIGHTY************///

#include <bits/stdc++.h>

using namespace std;

#define ll long long int

int main()

{

    ios_base::sync_with_stdio(0);

    cin.tie(0);

    ll  n,t,i,j,f;

    bool a[55][55];

    cin>>t;

    while(t--)

    {

        f=0;

        cin>>n;

        for(i=1; i<=n; i++)

        {

            for(j=1; j<=n; j++)

            {

                char c;

                cin>>c;

                a[i][j]=c-'0';

            }

        }

        for(i=1; i<n; i++)

        {

            for(j=1; j<n; j++)

            {

                if(a[i][j]==1&&a[i][j+1]==0&&a[i+1][j]==0)

                {

                    f=1;

                    break;

                }

            }

        }

        if(f==0)

            cout<<"YES"<<endl;

        else

            cout<<"NO"<<endl;

    }

}