[LintCode] 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

X轴上两指针的距离right - left为矩形长；
Y轴取两个指针所指的较短边：
Math.min(heights[left], heights[right])作为宽，相乘所得max为最大装水容量。将两指针向中间移动，更新max的最大值。

参考：
https://segmentfault.com/a/1190000003815582

Solution

public class Solution {
    public int maxArea(int[] heights) {
        // write your code here
        int left = 0, right = heights.length - 1, max = 0;
        while (left < right) {
            max = Math.max(max, Math.min(heights[left], heights[right]) * (right - left));
            if (heights[left] < heights[right]) left++;
            else right--;
        }
        return max;
    }
}