【python3】leetcode 11. Container With Most Water (Medium)

11. Container With Most Water (Medium)

Given n non-negative integers a1, a2, ..., an , where each represents a point at coordinate (i, ai). nvertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together with x-axis forms a container, such that the container contains the most water.

Note: You may not slant the container and n is at least 2.

The above vertical lines are represented by array [1,8,6,2,5,4,8,3,7]. In this case, the max area of water (blue section) the container can contain is 49.

Example:

Input: [1,8,6,2,5,4,8,3,7]
Output: 49

1暴力破解

这道题很容易想到暴力破解，时间复杂度o(n2), java和c++都可以通过，然而 python会超时

2 two pointer

solution里的解法，两个指针指向首尾，每次挪动一格，只挪动较小的那个指针

每次的面积 =  (idx2 - idx1) * min(height[idx1],height[idx2])

class Solution:
    def maxArea(self, height):
        """
        :type height: List[int]
        :rtype: int
        """
        idx1 = 0
        idx2 = len(height) - 1
        most = 0
        while(idx1 < idx2):
            most = max(most,(idx2 - idx1) * min(height[idx1],height[idx2]))
            if height[idx1] < height[idx2]: idx1 += 1
            else:idx2 -= 1
            
        return most