原题链接: https://oj.leetcode.com/problems/set-matrix-zeroes/

public void setZeroes(int[][] matrix) {
    if (matrix == null) return;

    int m = matrix.length;
    int n = matrix[0].length;

    boolean[] row = new boolean[m];
    boolean[] col = new boolean[n];

    for (int i = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
            if (matrix[i][j] == 0) {
                row[i] = true;
                col[j] = true;
            }
        }
    }

    for (int i = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
            if (row[i] || col[j]) {
                matrix[i][j] = 0;                   
            }
        }
    }
}

public void setZeroesV2(int[][] matrix) {
    if (matrix == null) return;

    int m = matrix.length;
    int n = matrix[0].length;

    boolean firstRowZero = false;
    boolean firstColZero = false;

    for (int i = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
            if (matrix[i][j] == 0) {
                matrix[i][0] = 0;
                matrix[0][j] = 0;

                if (i == 0) firstRowZero = true;
                if (j == 0) firstColZero = true;
            }
        }
    }

    for (int i = 1; i < m; i++) {
        for (int j = 1; j < n; j++) {
            if (matrix[0][j] == 0 || matrix[i][0] == 0) matrix[i][j] = 0;
        }
    }

    if (firstRowZero) {
        for (int i = 0; i < n; i++) matrix[0][i] = 0;
    }

    if (firstColZero) {
        for (int i = 0; i < m; i++) matrix[i][0] = 0;
    }
}