O(n^2) - Quadratic Time

Nested loops that compare every pair.

for (let i = 0; i < items.length; i += 1) {
  for (let j = i + 1; j < items.length; j += 1) {
    compare(items[i], items[j]);
  }
}

Notes

• Acceptable for small n.
• Use hashing or indexing to reduce to O(n).