LeetCode: Set Matrix Zeroes

Java:

需要注意的是，题目要求不能有额外的空间，因此我们需要在矩阵上进行操作，不能直接将行和列置0，因此我们需要存储各行列的状态，但是首行首列的状态不能存在matrix[0][0]中，需要两个boolean变量来存储，而这两个boolean变量的初值则是matrix[0][0] == 0

public class Solution {
    public void setZeroes(int[][] matrix) {
        int m = matrix.length;
        int n = matrix[0].length;
        boolean rowZero = matrix[0][0] == 0;
        boolean columnZero = matrix[0][0] == 0;
        for (int i = 1; i < m; i++) {
            if (matrix[i][0] == 0) {
                columnZero = true;
                break;
            }
        }
        for (int i = 1; i < n; i++) {
            if (matrix[0][i] == 0) {
                rowZero = true;
                break;
            }
        }
        for (int i = 1; i < m; i++) {
            for (int j = 1; j < n; j++) {
                if (matrix[i][j] == 0) {
                    matrix[i][0] = 0;
                    matrix[0][j] = 0;
                }
            }
        }
        for (int i = 1; i < m; i++) {
            if (matrix[i][0] == 0) {
                for (int j = 1; j < n; j++) matrix[i][j] = 0;
            }
        }
        for (int j = 1; j < n; j++) {
            if (matrix[0][j] == 0) {
                for (int i = 1; i < m; i++) matrix[i][j] = 0;
            }
        }
        if (rowZero == true) {
            for (int j = 0; j < n; j++) matrix[0][j] = 0;
        }
        if (columnZero == true) {
            for (int i = 0; i < m; i++) matrix[i][0] = 0;
        }
    }
}