Selection Sort

Selection Sort is a simple sorting algorithm that divides an array into a sorted and an unsorted portion. It repeatedly selects the smallest value from the unsorted portion and moves it to the end of the sorted portion.

This algorithm is easy to understand, but not efficient for large datasets. It is mainly used for learning and small collections.

How It Works

Selection Sort works by selecting the smallest remaining element:

Start at the beginning of the array.
Assume the first unsorted element is the smallest.
Compare it with the rest of the unsorted elements.
Find the actual smallest value.
Swap it with the first unsorted element.
Move the boundary of the sorted portion forward.
Repeat until the entire array is sorted.

Each pass places one element into its correct position.

JavaScript Example


function selectionSort(arr) {
  const result = [...arr];

  for (let i = 0; i < result.length; i++) {
    let minIndex = i;

    for (let j = i + 1; j < result.length; j++) {
      if (result[j] < result[minIndex]) {
        minIndex = j;
      }
    }

    if (minIndex !== i) {
      // Swap values
      const temp = result[i];
      result[i] = result[minIndex];
      result[minIndex] = temp;
    }
  }

  return result;
}

// Example usage
const values = [64, 25, 12, 22, 11];

console.log(selectionSort(values)); // [11, 12, 22, 25, 64]