题解 | #上三角矩阵判定#
上三角矩阵判定
http://www.nowcoder.com/practice/f5a29bacfc514e5a935723857e1245e4
import java.io.*;
public class Main {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
int n = Integer.parseInt(br.readLine());
String[][] array = new String[n][n];
for (int i = 0; i < n; i++) {
String[] arr = br.readLine().split(" ");
for (int j = 0; j < n; j++) {
array[i][j] = arr[j];
}
}
System.out.println(judge(array, n));
}
public static String judge(String[][] arr, int row) {
for (int i = 0; i < row; i++) {
for (int j = 0; j < i; j++) {
if (Integer.parseInt(arr[i][j]) != 0) {
return "NO";
}
}
}
return "YES";
}
}
