PTA 实验7-2-5 判断上三角矩阵 (15point(s)) Easy only once

#include<stdlib.h>
#include<stdio.h>
#define maxn 21

int n,num;

int ma[maxn][maxn];

int charge(int n) {
    //判断是否是上三角
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < i; j++) {
            if (ma[i][j] != 0)
                return 0;
        }
    }
    return 1;
}

int main(){
    int a;
    scanf("%d", &num);
    for (int i = 0; i < num; i++) {
        scanf("%d",&n);
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                scanf("%d", &ma[i][j]);
            }
        }
        //进行判断；
        if (charge(n) == 1) {
            //如果是上三角矩阵；
            printf("YES\n");
        }
        else {
            printf("NO\n");
        }
    }
    return 0;
}