[Solved] Given an array of integers heights representing the histogram’s bar height where the width of each bar is 1, return the area of the largest rectangle in the histogram.

Question

Given an array of integers heights representing the histogram’s bar height where the width of each bar is 1, return the area of the largest rectangle in the histogram.

Example 1:

histogram
Input: heights = [2,1,5,6,2,3]
Output: 10
Explanation: The above is a histogram where width of each bar is 1.
The largest rectangle is shown in the red area, which has an area = 10 units.

Example 2:

histogram 1
Input: heights = [2,4]
Output: 4

Constraints:

  • 1 <= heights.length <= 105
  • 0 <= heights[i] <= 104

Python Solution

class Solution:
    def largestRectangleArea(self, A: List[int]) -> int:
        stack = []
        maxi = 0
        i = 0
        while i<len(A):
            if len(stack)==0 or A[stack[-1]]<=A[i]:
                stack.append(i)
                i+=1
            else:
                top = stack.pop()
                if len(stack)==0:
                    ar = A[top]*(i)
                else:
                    ar = A[top]*(i-stack[-1]-1)
                maxi = max(maxi,ar)

        while len(stack)!=0:
            top = stack.pop()
            if len(stack)==0:
                ar = A[top]*(i)
            else:
                ar = A[top]*(i-stack[-1]-1)
            maxi = max(maxi,ar)

        return(maxi)
Abhishek Sharma
Abhishek Sharma

Started my Data Science journey in my 2nd year of college and since then continuously into it because of the magical powers of ML and continuously doing projects in almost every domain of AI like ML, DL, CV, NLP.

Articles: 520

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