Selection Sort

Scans the unsorted region for its minimum and swaps it to the front. Always exactly n−1 swaps, which matters when writes are expensive — but comparisons stay O(n²).

Category: Sorting
Time complexity: O(n²)
Space complexity: O(1)

Pseudocode

for i ← 0 to n−2
  min ← i
  scan j ← i+1..n−1 for smaller
  swap A[i], A[min]
done

Reference implementation

for i in range(n - 1):
    m = i
    for j in range(i + 1, n):
        if a[j] &lt; a[m]: m = j
    a[i], a[m] = a[m], a[i]

Open the interactive Selection Sort visualisation →