【leetcode刷题】20T37-矩阵置零

示例 1:
输入: 
[
  [1,1,1],
  [1,0,1],
  [1,1,1]
]
输出: 
[
  [1,0,1],
  [0,0,0],
  [1,0,1]
]

示例 2:
输入: 
[
  [0,1,2,0],
  [3,4,5,2],
  [1,3,1,5]
]
输出: 
[
  [0,0,0,0],
  [0,4,5,0],
  [0,3,1,0]
]

class Solution(object):
    def setZeroes(self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: None Do not return anything, modify matrix in-place instead.
        """
        rows = []
        cols = set()
        for i in range(len(matrix)):
            current_cols = []
            for j in range(len(matrix[0])):
                if matrix[i][j] == 0:
                    current_cols.append(j)

            if len(current_cols) != 0:
                rows.append(i)
            cols.update(current_cols)

        for i in rows:
            # 一行转换为0
            for k in range(len(matrix[0])):
                matrix[i][k] = 0

        for j in set(cols):
            # 则一列转换为0
            for k in range(len(matrix)):
                matrix[k][j] = 0