Leetcode: Maximal Rectangle @Python

class Solution:
    # @param matrix, a list of lists of 1 length string
    # @return an integer
    def largestRectangleArea(self, height):
        height.insert(0,0)
        height.append(0)
        n=len(height)
        stack=[0]
        maxRec=0
        for i in range(1,n):
            while height[i]<height[stack[-1]]:
                k=stack.pop()
                newarea=(i-1-stack[-1])*height[k]
                if newarea>maxRec:
                    maxRec=newarea
            stack.append(i)
        height.pop()
        height.pop(0)
        return maxRec
    def maximalRectangle(self, matrix):
        maxRec=0
        m=len(matrix)
        if m>0:
            n=len(matrix[0])
        else:
            return 0
        height=[[0 for i in range(n)] for j in range(m)]
        for i in range(m):
            for j in range(n):
                if i==0:
                    height[i][j]=int(matrix[i][j])
                elif matrix[i][j]=='0':
                    height[i][j]=0
                else :
                    height[i][j]=height[i-1][j]+1
            maxRec=max(maxRec,self.largestRectangleArea(height[i]))
        return maxRec