Data Structures -> Pairing Heap / Leftist Heap

Use a meldable heap when many singleton heaps keep unioning and the real primitive is merge rather than push.

• Topic slug: data-structures/pairing-leftist-heap
• Tutorial page: Open tutorial
• Ladder page: Open ladder
• Repo problems currently tagged here: 1
• Repo companion pages: 4
• Curated external problems: 2

Microtopics

• meldable-heap
• leftist-heap
• pairing-heap
• merge
• delete-min
• owner-tracking

Learning Sources

Source	Type
OI Wiki leftist tree	Reference
OI Wiki pairing heap	Reference
Luogu P3377	Practice

Practice Sources

Source	Type
Luogu P1456	Practice

Repo Companion Material

Material	Type
Pairing / Leftist Heap hot sheet	quick reference
Mergeable Heap 1	flagship note
Heaps And Ordered Sets	compare point
Template Library exact starter route	starter route

Curated External Problems

Core

Problem	Source	Difficulty	Context	Style	Prerequisites	Tags	Why it fits
P3377 [Template] Mergeable Heap 1	Luogu	Medium	Meldable-Heap, Leftist-Heap	Data-Structure-Heavy; Implementation	Priority Queues; Heap Merge; Owner Tracking	Delete Min; DSU; Simulation	The cleanest verifier-style first rep where every item starts in its own heap, heaps meld online, and delete-min is asked by naming one item's current heap.

Challenge

Problem	Source	Difficulty	Context	Style	Prerequisites	Tags	Why it fits
P1456 Monkey King	Luogu	Hard	Meldable-Heap	Data-Structure-Heavy; Implementation	Heap Merge; Delete Min; Owner Tracking	Leftist Heap; Heap Merge	A classic follow-up where the same meldable-heap route survives after each duel mutates the current roots before the heaps merge again.

Repo Problems

Code	Title	Fit	Difficulty	Pattern	Note	Solution
MERGEABLEHEAP1	P3377 [Template] Mergeable Heap 1	primary	medium	-	Note	Code

Regeneration

python3 scripts/generate_problem_catalog.py