leetcode 11. Container With Most Water (two pointer)

2017-04-13 · 1 min read · two pointer leetcode

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.

题意：n条竖直的线段 (i,0)->(i,a[i]),从中选2条，和x轴共同组成一个开口的容器，问容器的最大面积。

思路：一开始想错了，以为是最大连续矩形面积...还在想leetcode竟然考单调栈？？？

然而实际上只取两个线段，中间的线段有没有，长度，都是无所谓的。

因此two pointer就好了。。。

1/* ***********************************************
2Author :111qqz
3Created Time :2017年04月13日 星期四 18时06分42秒
4File Name :11.cpp
5 ************************************************ */
6class Solution {

    public:

 1	int maxArea(vector<int>& height) {
 2	    int res = 0 ;
 3	    int n = height.size();
 4	    int head = 0 ;
 5	    int tail = n-1;
 6	    while (head<tail)
 7	    {
 8		int h = min(height[head],height[tail]);
 9		res = max(res,(tail-head)*h);
10		while (head<tail&&height[head]<=h) head++;
11		while (head<tail&&height[tail]<=h) tail--;
12	    }
13	    return res;

	}

};