【leetcode】Container With Most Water

一、问题描述

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.

二、问题分析

刚开始以为是一道DP的题，但分析了一下状态转移方程表较难写，看了一下题目下面的tag，提示说是一道双指针的问题。于是从双指针入手，维护一左一右两个指针，从两头开始逐渐收敛，然后维护一个max值。这里需要明确的是容器的容量由短板决定！因此在收敛的时候，从短板开始。

三、Java AC 代码

public int maxArea(int[] height) {
		int max = 0;
		if (height == null || height.length < 2) {
			return max;
		}
		int left = 0, right = height.length - 1;
		while (left < right) {
			int tmp = Math.min(height[left], height[right]) * (right - left);
			if (tmp > max) {
				max = tmp;
			}
			if (height[right]<height[left]) {
				int key = height[right];
				while(--right > left && height[right] < key);
			}else {
				int key = height[left];
				while(++left < right && height[left] < key);
			}
		}
		return max;
	}