What is the time complexity for LeetCode 84 largest rectangle in histogram?

O(n). Each index pushed/popped once.

How does monotonic stack work in LeetCode 84?

Maintains increasing order. Pop when violated, compute trapped rectangle.

Yes, two arrays for left/right smaller. Still O(n), more code.

What if the biggest rectangle in a histogram hides the flaw in your coding brain? LeetCode 84 forces you to confront it, stack and all.

theAIcatchup Apr 09, 2026 3 min read

Monotonic stack nails O(n) for histogram max area — elegant but interview-trappy. 𝕏
TraceLit visualizer beats paper sketches for debugging the pops. 𝕏
LeetCode 84 recycles old tricks; AI will soon make it obsolete. 𝕏

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#LeetCode 84 #TraceLit #algorithm visualization #coding interviews #histogram algorithm #histogram rectangle #largest rectangle histogram #leetcode hard #monotonic stack

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Originally reported by dev.to