Min Heap

Heap property, array representation, and heapify operations.

5 min readMastering Data Structures & Algorithms for Software Engineering InterviewsCode

Heap Property

A min heap is a complete binary tree where each node's value ≤ its children's values. Root is always minimum. Max heap reverses the inequality. Heaps enable O(1) min/max access and O(log n) insertion/deletion.

Array Representation

Heaps use array (slice) with implicit tree structure. For 0-indexed array: left child = 2*i+1, right child = 2*i+2, parent = (i-1)/2. No pointers needed.

Gomin-heap-structure.go

14 linesLn 1, Col 1Go

Simple index math for tree navigation. No explicit node objects needed.

Core Operations

Gopush-and-pop.go

42 linesLn 1, Col 1Go

Push: append, sift up (swap with parent while smaller). Pop: swap root with last, remove last, sift down (swap with smaller child while larger). Both O(log n).

Heapify

Build heap from unsorted array in O(n) by sifting down from last non-leaf node to root. Better than n pushes (O(n log n)).

Goheapify.go

7 linesLn 1, Col 1Go

Start from last parent (n/2-1). Sift down each. Leaves are already valid heaps. Total O(n).

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