---
title: 'Auxiliary Ordering Structures'
description: 'You do not traverse them; you maintain them while traversing something else.'
sidebar:
  order: 1
  label: Introduction
---

:::warning[Under construction]
This page is a scaffold. Notes, canonical problems, and template code are not written yet.
:::

## Patterns

- [Stack](/guides/coding/auxiliary-ordering/stack) — LIFO memory of unresolved items; monotonic stack discards dominated candidates.
- [Heap](/guides/coding/auxiliary-ordering/heap) — Partial order: cheap access to the extremum without a full sort.

**Systems anchor:** Monotonic stack is log compaction; heap is priority scheduling, Dijkstra's frontier, timer wheels.