Largest Histogram ​
Largest Histogram — LeetCode
Given bar heights of a histogram, find the area of the largest rectangle that fits inside it.
Approach ​
Iterate through each element. The top of the stack should be lesser than the current element -> Push current element with startIndex = i. Else, while top of stack is greater, pop the stack and calculate the maxArea. Push the current element at the end with startIndex = index of last popped element.
Calculate area for rest of the elements