73. 矩阵置零

leetcode链接：
https://leetcode.cn/problems/set-matrix-zeroes/description/

方案一

暴力求解

List<int[]> ls = new ArrayList<>();

// 找到数值为0的位置
for (int i = 0; i < matrix.length; i++) {
	for (int j = 0; j < matrix[i].length; j++) {
		if (matrix[i][j] == 0)
		ls.add(new int[]{i, j});
	}
}

// 修改相关变量
for (int[] is : ls) {
	for (int i = 0; i < matrix.length; i++) {
		matrix[i][is[1]] = 0;
	}
	for (int i = 0; i < matrix[is[0]].length; i++) {
		matrix[is[0]][i] = 0;
	}
}

几乎最优方案

https://leetcode.cn/problems/set-matrix-zeroes/solution/ju-zhen-zhi-ling-by-leetcode-solution-9ll7/

class Solution {
    public void setZeroes(int[][] matrix) {
        int m = matrix.length, n = matrix[0].length;
        boolean flagCol0 = false;
        for (int i = 0; i < m; i++) {
            if (matrix[i][0] == 0) {
                flagCol0 = true;
            }
            for (int j = 1; j < n; j++) {
                if (matrix[i][j] == 0) {
                    matrix[i][0] = matrix[0][j] = 0;
                }
            }
        }
        for (int i = m - 1; i >= 0; i--) {
            for (int j = 1; j < n; j++) {
                if (matrix[i][0] == 0 || matrix[0][j] == 0) {
                    matrix[i][j] = 0;
                }
            }
            if (flagCol0) {
                matrix[i][0] = 0;
            }
        }
    }
}

作者：LeetCode-Solution
链接：https://leetcode.cn/problems/set-matrix-zeroes/solution/ju-zhen-zhi-ling-by-leetcode-solution-9ll7/
来源：力扣（LeetCode）
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