【LeetCode with Python】 Container With Most Water

博客域名：http://www.xnerv.wang
原题页面：https://oj.leetcode.com/problems/container-with-most-water/
题目类型：两指针问题
难度评价：★★★
本文地址：http://blog.csdn.net/nerv3x3/article/details/37331325

Given n non-negative integers a₁, a₂, ...,a_n, where each represents a point at coordinate (i,a_i).n vertical lines are drawn such that the two endpoints of linei is at (i,a_i) 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.

用两个指针从数组的左边和右边开始，向中间搜索。依据的理由有两点：
1、因为一开始底边长就已经是最大，两个指针向中间移动的时候，底边长只会变短，因此如果此时面积要变大的话，只能是两条高中的最短者比移动前的最短高更高，否则就无需考察，直接continue到下一次的循环。
2、因此，每次选择移动左指针还是右指针，优先选择当前高度最短的那个，以期寻找到更高的边。如果此时选择移动当前高度最高的那个，就有可能跳过了最优解。

class Solution:    # @return an integer    def maxArea(self, height):        len_height = len(height)        if 1 == len_height:            return 0        max_area = 0        left_index = 0        right_index = len_height - 1        while left_index < right_index:            if height[left_index] < height[right_index]:                area = (right_index - left_index) * height[left_index]                left_index += 1            else:                area = (right_index - left_index) * height[right_index]                right_index -= 1            if area > max_area:                    max_area = area        return max_area