刷java算法题出现了空指针错误

Question

public class Solution { public void setZeroes(int[][] matrix) { int m = matrix.length; int n = matrix[0].length; Boolean[] rows = new Boolean[m]; Boolean[] cols = new Boolean[n]; for(int i = 0; i< m; i++){ for(int j = 0; j< n; j++){ if(matrix[i][j] == 0){ rows[i] = true; cols[j] = true; } } } for(int i = 0; i<m; i++){ for(int j = 0; j< n; j++){ if(rows[i] ==true || cols[j] == true) matrix[i][j] = 0; } } } } 该题是leetcode第73题Set Matrix Zeroes，题目如下： Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place.我的做法是，加一个行数组、一个列数组，来记录哪些行、哪些列有0，但是提交时出现了空指针错误。