LeetCode 84 Largest Rectangle in Histogram - Problem Statement

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

With [2, 1, 5, 6, 2, 3]:

• A rectangle of height 5 spanning bars 2-3 has area 5 × 2 = 10.
• A rectangle of height 2 spanning bars 0-5 has area 2 × 6 = 12. But bar 1 is only height 1, so this doesn't work.
• The largest is 10 (bars 2-3 with height 5).

For each bar, imagine extending it left and right as far as possible while maintaining at least that height.

Constraints: $1 \le$ bars $\le 10^5$.