#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# max water
# @param arr int整型一维数组 the array
# @return long长整型
#
class Solution:
    def maxWater(self , arr: List[int]) -> int:
        # write code here
        res = 0
        if not arr or len(arr)<=2:
            return res
        i,j = 0,len(arr)-1
        left,right = arr[i],arr[j]
        while i<j:
            l,r = arr[i],arr[j]
            if l<r:
                if l < min(left,right):
                    res += min(left,right) - l
#                     print(i,min(left,right),l)
                i += 1
                left = max(arr[i],left)
            else:
                if r< min(left,right):
                    res += min(left,right) - r
#                     print(i,min(left,right),r)
                j -= 1
                right = max(arr[j],right)
        return res