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.
1 遍历的时候以width为变量
2 L指向左边，R指向右边，如果height[L]<height[R], 如果移动高的那个，也就是左移R，有以下情况：
（1）左移后，height[R]<height[L]，则容器变小
（2）左移后，height[R]>height[L]，则容器也变小
（3）左移后，height[R]=height[L]，因为底变短了，则容器也变小
所以移动矮的那个指针才有用
1 基本思路是双指针，每一次遍历都更新water数，对于左右指针，每次移动矮的那个，木桶原理
