Largest Rectangle in Histogram

Given an array heights representing bar heights in a histogram, return the area of the largest rectangle that can be formed.

Function signature

func LargestRectangleArea(heights []int) int

Example

heights = [2,1,5,6,2,3]
output = 10

Constraints

• 0 <= len(heights) <= 200_000
• 0 <= heights[i] <= 1_000_000_000

Notes

• Use a monotonic increasing stack of indices.
• A sentinel height of 0 flushes remaining bars.