View Code of Problem 51

#include <iostream>
#include <cstdio>
using namespace std;
int main(){
    int n,a[999][999],sum=0;
    cin>>n;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            cin>>a[i][j];
        }
        for(int j=i;j>=0;j--){
            sum+=a[i][j];
        }
    }
    cout<<sum<<endl;
    return 0;
}