73.设置数组为0

Set Matrix Zeroes

问题描述：

Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place.

测试代码（Python）：

class Solution(object):    def setZeroes(self, matrix):        """        :type matrix: List[List[int]]        :rtype: void Do not return anything, modify matrix in-place instead.        """        row = [False for r in range(len(matrix))]        column = [False for r in range(len(matrix[0]))]        for i in range(len(matrix)):            for j in range(len(matrix[0])):                if matrix[i][j]==0:                    row[i] = True                    column[j] = True        for i in range(len(matrix)):            for j in range(len(matrix[0])):                if row[i] or column[j]:                    matrix[i][j] = 0        

性能：

参考答案（c++）：

class Solution {public:    void setZeroes(vector<vector<int> > &matrix) {        int col0 = 1, rows = matrix.size(), cols = matrix[0].size();        for (int i = 0; i < rows; i++) {            if (matrix[i][0] == 0) col0 = 0;            for (int j = 1; j < cols; j++)                if (matrix[i][j] == 0)                    matrix[i][0] = matrix[0][j] = 0;        }        for (int i = rows - 1; i >= 0; i--) {            for (int j = cols - 1; j >= 1; j--)                if (matrix[i][0] == 0 || matrix[0][j] == 0)                    matrix[i][j] = 0;            if (col0 == 0) matrix[i][0] = 0;        }    }};

性能：