Container With Most Water in Python

Suppose we have a set of n non-negative integers a1, a2, ..., an,each value represents a point at coordinate (i, a[i]). n vertical lines are present in such a way that the two endpoints of line i is at (i, a[i]) and (i, a[0]). We have to find two lines, which together with x-axis forms one container, so our goal is to find two columns where water volume is max. So if the array is like [1,8,6,2,5,4,8,3,7], then it will be

In the shaded part, the height is 7 and there are 7 sections, so the total area is actually 7 * 7 = 49. This is the output.

To solve this, we will follow these steps

• low := 0, high := length of arr – 1, ans := 0
• while low < high
  • if arr[low] < arr[high]: min_h := height[low] and min_ind := low
  • otherwise min_h := height[high] and min_ind := high
  • ans := maximum of (high – low)* min_h and ans
  • if low + 1 = min_ind + 1, then increase low by 1 otherwise decrease high by 1
• return ans

Example

Let us see the following implementation to get better understanding −

 Live Demo

class Solution(object):
   def maxArea(self, height):
      low = 0
      high = len(height) - 1
      ans = 0
      while low < high:
         if height[low]<height[high]:
            min_height = height[low]
            min_height_index = low
         else:
            min_height = height[high]
            min_height_index = high
         ans = max(((high - low) ) * min_height,ans)
         if low+1==min_height_index+1:
            low+=1
         else:
            high-=1
      return ans
ob1 = Solution()
print(ob1.maxArea([1,8,6,2,5,4,8,3,7]))

Input

[1,8,6,2,5,4,8,3,7]

Output

49