#sorting
Selection Sort
Introduction Selection Sort works by repeatedly finding the minimum element from the unsorted portion and placing it at the beginning. It’s like sorting a hand of cards by scanning for the smallest card each time and moving it to the front. Selection Sort is simple to understand and implement, but it’s always O(n²) — even on sorted input. It makes the minimum number of swaps (at most n-1), which can matter when writes are expensive. Read more →
March 31, 2026
Insertion Sort
Introduction Insertion Sort builds a sorted array one element at a time by picking each element and inserting it into its correct position among the already-sorted elements. It’s exactly how most people sort a hand of playing cards — you pick up one card at a time and slide it into the right spot. Despite being O(n²) in the worst case, Insertion Sort is genuinely useful. It’s the fastest algorithm for small arrays and nearly-sorted data, which is why many standard library sort implementations (like TimSort) use it as a building block. Read more →
March 31, 2026
Bubble Sort
Introduction Bubble Sort is the simplest sorting algorithm. It repeatedly steps through the array, compares adjacent elements, and swaps them if they’re in the wrong order. The largest unsorted element “bubbles up” to its correct position on each pass — like air bubbles rising to the surface of water. Nobody uses Bubble Sort in production (it’s too slow), but it’s worth understanding because it’s often the first sorting algorithm taught, it appears in interviews as a baseline comparison, and optimizing it teaches useful concepts. Read more →
March 31, 2026
Merge Sort
Introduction Merge Sort is a divide-and-conquer sorting algorithm that splits an array in half, recursively sorts each half, then merges the two sorted halves back together. It’s like sorting a deck of cards by splitting it into smaller and smaller piles until each pile has one card, then merging piles together in order. Unlike Quick Sort, which can degrade to O(n²) with bad pivot choices, Merge Sort guarantees O(n log n) in every case. Read more →
March 31, 2026
Quick Sort
Introduction Quick Sort is a divide-and-conquer sorting algorithm that works by picking a “pivot” element and partitioning the array so that everything smaller goes to the left and everything larger goes to the right. Then it recursively sorts each side. It’s like organizing a messy bookshelf by picking a book in the middle, putting everything shorter to the left and taller to the right, then repeating for each side. Quick Sort is one of the most widely used sorting algorithms in practice — it’s the default in many standard library implementations because of its excellent average-case performance and low overhead. Read more →
March 31, 2026