Set matrix Zeroes Leetcode-73

class Solution(object):
    def setZeroes(self, matrix):
        dictr={}
        dictc={}
        r=len(matrix)
        c=len(matrix[0])
        for i in range(r):
                for j in range(c):
                    if  matrix[i][j]==0:
                        dictr[i]=True
                        dictc[j]=True
        for i in range(r):
            for j in range(c):
                if i in dictr or j in dictc:
                    matrix[i][j]=0
        return matrix