DSA

Monotonic Structures

Go beyond basic stacks and queues with Monotonic structures to solve range queries and boundary problems.

By TechCoder TeamLast updated: 2026-06-02
In a Nutshell

Go beyond basic stacks and queues with Monotonic structures to solve range queries and boundary problems. This hands-on tutorial focuses on practical implementation of monotonic structures concepts.

Monotonic Structures

A Monotonic Structure maintains its elements in a specific order (always increasing or always decreasing). This is powerful for problems involving "nearest" elements or finding minimums/maximums in a sliding window.

1. Monotonic Stack Recap

We use a monotonic decreasing stack to find the Next Greater Element.

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2. Largest Rectangle in Histogram

This is a classic "hard" problem solved beautifully with a monotonic stack.

The area 5x2 = 10 is the maximum.

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3. Monotonic Queue

Used primarily for the Sliding Window Maximum (which we covered in Module 6). It allows us to get the max element in $O(1)$ while sliding the window in $O(1)$ amortized.

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Quiz

Quiz

Question 1 of 1

What property does a 'Monotonic Increasing' stack maintain?

Elements are popped if they are smaller than the new element
Elements are popped if they are larger than the new element
It functions exactly like a priority queue
It only accepts integers