题解 | 上三角矩阵判定
上三角矩阵判定
https://www.nowcoder.com/practice/f5a29bacfc514e5a935723857e1245e4
n = int(input()) for i in range(n): row = list(map(int, input().split())) if row.count(0) != i: for _ in range(i + 1, n): input() print('NO') exit() print('YES')