题目描述
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.
Example 1:
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.
Example 2:
Input: height = [1,1]
Output: 1
思路
找到能够盛水最多的两块挡板并返回它们围成的矩形的面积，有点类似于接雨水。我们这里采用双指针的解法，一左一右两个指针分别代表容器的左边和右边，不断向中间逼近并计算所围成的矩形面积。由于该矩形的高是由两条边中较短的一条来决定的，因此哪条边短我们就收缩哪边。时间复杂度 O(N)，空间复杂度 O(1)
代码参考
class Solution:
def maxArea(self, height: List[int]) -> int:
# T: O(n), S: O(1)
l, r = 0, len(height) - 1
res = 0
while l < r:
curr_area = min(height[l], height[r]) * (r - l)
res = max(res, curr_area)
if height[l] < height[r]:
l += 1
else:
r -= 1
return res
