42. Trapping Rain Water - LeetCode Solution

class Solution:
    def trap(self, height: List[int]) -> int:
        maxl = []
        maxr = []
        if(len(height) == 0):
            return 0

        maxl.append(height[-1])
        maxr.append(height[0])

        for i in range(1, len(height), 1):
            maxr.append(max(height[i], maxr[-1]))


        for i in range(len(height) - 2, -1, -1):
            maxl.append(max(height[i], maxl[-1]))


        count = 0

        maxl.reverse()


        for i in range(len(height)):
            count+= min(maxr[i], maxl[i]) - height[i]

        return count