leecode_11. Container With Most Water

https://leetcode.com/problems/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.

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題意：給你一個數組，從a1，a2...an，來描述n個點：（1，a1）、（2，a2）、（i，ai）、（n，an），對每個點畫一條線垂直於x軸，任選兩條線作爲玻璃，問往裏面倒水最多能倒多少？

解答：一開始寫了個暴力，結果超時了。後來優化了一下，假設a1爲短板，那麼要使a1爲玻璃，那麼要距離它最遠的比它長的線，找到即可。

class Solution {
public:
    int maxArea(vector<int>& height) {
        int size = height.size();
        int ans = 0;
        for(int i=0;i<size;i++)
        {
            int l=0,r=size-1;
            while(height[i]>height[r])
            {
                r--;
            }
            while(height[i]>height[l])
            {
                l++;
            }
            ans=max(ans,height[i]*(r-i));
            ans=max(ans,height[i]*(i-l));
        }
        
        return ans;
    }
    
};