Promble

link: https://leetcode.com/problems/container-with-most-water/

You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]).

Find two lines that together with the x-axis form a container, such that the container contains the most water.

Return the maximum amount of water a container can store.

Notice that you may not slant the container.

Input: height = [1,8,6,2,5,4,8,3,7]
Output: 49
Explanation: 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.

Input: height = [1,1]
Output: 1

Approach

Thought

1. 设定两个指针, left, right = 0, len(height) - 1
2. 暂存变量ans=0
3. 循环判断left < right
   1. 如果height[left] < height[right], area = height[left] * (right - left), left+=1
   2. 反之，area = height[right] * (right - left), right -= 1
4. 返回max(ans, area)
5. 直到left > right, 返回ans的值

📓前后同时比较，这样可以确定一边是高的，然后移动另一边。 必须是left < right的情况，其余不需要比较。

Code

class Solution:
    def maxArea(self, height: List[int]) -> int:
        
        left, right = 0, len(height) - 1 
        ans = 0 

        while left < right:
            if height[left] < height[right]:
                area = height[left] * (right - left)
                left += 1 
            else:
                area = height[right] * (right - left)
                right -= 1
            ans = max(ans, area)

        return ans