class Solution(object):
    def setZeroes(self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: void Do not return anything, modify matrix in-place instead.
        """
        if not matrix:
            return
        zeroRows = set()
        zeroColumns = set()
        rows = len( matrix )
        columns = len( matrix[ 0 ] )
        for i in range( rows ):
            row = matrix[ i ]
            for j in range( columns ):
                item = row[ j ]
                if item == 0:
                    zeroRows.add( i )
                    zeroColumns.add( j )
        for i in zeroRows:
            row = matrix[ i ]
            for k in range( columns ):
                row[ k ] = 0
        for j in zeroColumns:
            for i in range( rows ):
                matrix[ i ][ j ] = 0