Bubble Sort isn't used in production — but it's the best algorithm to learn sorting logic because every step is visible and intuitive.
🔹 The Idea
Repeatedly compare adjacent elements. If wrong order, swap. Larger elements "bubble up" to the end.
📋 Step-by-Step: [5, 3, 8, 2]
Pass 1: 5↔3 → 5 vs 8 → 8↔2 → [3, 5, 2, **8**]
Pass 2: 3 vs 5 → 5↔2 → [3, 2, **5**, 8]
Pass 3: 3↔2 → [**2**, **3**, 5, 8] ✅
💻 Optimised JavaScript
function bubbleSort(arr) {
const n = arr.length;
for (let i = 0; i < n - 1; i++) {
let swapped = false;
for (let j = 0; j < n - i - 1; j++) {
if (arr[j] > arr[j + 1]) {
[arr[j], arr[j + 1]] = [arr[j + 1], arr[j]];
swapped = true;
}
}
if (!swapped) break; // Early exit — O(n) best case
}
return arr;
}
⏱ Complexity
| Case | Time | Space | Stable |
|---|---|---|---|
| Best (sorted) | O(n) | O(1) | ✅ |
| Average | O(n²) | O(1) | ✅ |
| Worst (reversed) | O(n²) | O(1) | ✅ |
Part 7 of the Bitveen DSA Series. Originally published at bitveen.com