Container With Most Water

Problem

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.

Example

Given [1,3,2], the max area of the container is 2.

Note

You may not slant the container.

Solution

Use 2 pointers from the 2 ends, move them towards the center until they meet. Every time calculate the amount of water and update the max, then move the short height pointer by 1.