11. Container With Most Water

题目

Given n non-negative integers a1, a2, ..., an , where each represents a point at coordinate (i, ai). n vertical 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 1:

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

题目大意

给出一个非负整数数组 a1，a2，a3，…… an，每个整数标识一个竖立在坐标轴 x 位置的一堵高度为 ai 的墙，选择两堵墙，和 x 轴构成的容器可以容纳最多的水。

解题思路

这一题也是对撞指针的思路。首尾分别 2 个指针，每次移动以后都分别判断长宽的乘积是否最大。