Leetcode 11. Container With Most Water

題目：

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.

例子：

Input: [1,8,6,2,5,4,8,3,7]
Output: 49

思路：

暴力，複雜度$n^2$
兩邊縮小到中間，每次都留下比較高的那邊，縮短比較矮的那邊。

代碼（暴力）：

class Solution {
public:
    int maxArea(vector<int>& height) {
        int max= 0;
        int tank_h, tank_w;
        for(int i = 0; i < height.size(); i++){
            
            for(int j=i+1; j<height.size(); j++){
                    
                tank_h = height[i]>height[j]? height[j]: height[i];
                tank_w = j-i;
                max = tank_h*tank_w > max? tank_h*tank_w:max;
                
            }
        }
        return max;
    }
};

代碼（兩點法）：