Selection sort is a simple sorting algorithm. This sorting algorithm is an in-place comparison-based algorithm in which the list is divided into two parts, the sorted part at the left end and the unsorted part at the right end. Initially, the sorted part is empty and the unsorted part is the entire list.

The smallest element is selected from the unsorted array and swapped with the
leftmost element, and that element becomes a part of the sorted array. This process continues moving unsorted array boundary by one element to the right.

This algorithm is not suitable for large data sets as its average and worst case
complexities are of Ο(n2), where n is the number of items.

Algorithm:

Step 1 − Set MIN to location 0
Step 2 − Search the minimum element in the list
Step 3 − Swap with value at location MIN
Step 4 − Increment MIN to point to next element
Step 5 − Repeat until list is sorted

Program:

public class SelectionSortExample {
public static void selectionSort(int[] arr)
{
for (int i = 0; i < arr.length - 1; i++)
{
int index = i;
for (int j = i + 1; j < arr.length; j++)
{
if (arr[j] < arr[index])
{
index = j;//searching for lowest
}
}
int smallerNumber = arr[index];
arr[index] = arr[i];
arr[i] = smallerNumber;
}
}
public static void main(String a[])
{
int[] arr1 = {9,14,3,2,43,11,58,22};
System.out.println("Before Selection");
for(int i:arr1)
{
System.out.print(i+" ");
}
System.out.println();
selectionSort(arr1);//sorting array using
System.out.println("After Selection Sort");
for(int i:arr1)
{
System.out.print(i+" ");
}
}
}

Output:

Before Selection Sort
9 14 3 2 43 11 58 22
After Selection Sort
2 3 9 11 14 22 43 58
Selection Sort

There are other sorting algorithms are available like Bubble sort, Insertion Sort, Merge sort, Quick sort, etc.

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