11. Container With Most Water

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.

The above vertical lines are represented by array [1,8,6,2,5,4,8,3,7]. In this case, the max area of water (blue section) the container can contain is 49.

Example:

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

 

至今无法理解怎么想出这种方法的.

从两端向中间逼近. 面积=宽(j-i) x 高 

接下来选择i,j中比较矮的向中间靠近即可.

 

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