#include <iostream> using namespace std; int arr[105][105]; int main() { int n; while (scanf("%d", &n) != EOF) { // 注意 while 处理多个 case for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { scanf("%d", &arr[i][j]); } } int i, j; for (i = 0; i < n; i++) { for (j = 0; j < n; j++) { if(i == j){ //对角线的元素不用检查 continue; }else{ int t1 = arr[i][j]; int t2 = arr[j][i]; if(t1 != t2){ break; } } } if(j < n){ break; } } if(j < n){ printf("No!\n"); }else{ printf("Yes!\n"); } } } // 64 位输出请用 printf("%lld")