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What Is a Min Heap?

Explore the concept of min heaps, a complete binary tree where the smallest element is the root. Learn how to implement and manipulate min heaps in Go, including inserting elements, extracting the minimum, peeking at the root, and checking size. Understand their applications and time complexities to use them effectively in algorithms requiring efficient access to the smallest element.

Min heap

A min heap is a complete binary tree where every parent node is smaller than or equal to its children, meaning the smallest element in the entire heap is always at the root and can be accessed immediately.

Example: Consider a min heap containing the values: [2, 5, 8, 10, 14].

Visualization of a min heap
Visualization of a min heap

The root is 2 because it is the smallest element. Its children are 5 and 8, both of which are greater than 2. Similarly, 5's children are 10 and 14, both of which are greater than 5. This ordering holds at every level of the tree, which makes it a valid min heap.

In slice form, this heap is stored as [2, 5, 8, 10, 14], with the root at index 0.

Understanding the index formulas

For any element at index i, its parent and children can be located using simple arithmetic:

  • Parent: (i1)//2(i - 1) // 2

  • Left child: 2×i+12 \times i + 1

  • Right child: 2i+22 * i + 2 ...