Selection Sort

CODE

Selection Sort

The selection sort algorithm sorts an array by repeatedly finding the minimum element (considering ascending order) from unsorted part and putting it at the beginning. The algorithm maintains two subarrays in a given array.

1) The subarray which is already sorted.  2) Remaining subarray which is unsorted.

In every iteration of selection sort, the minimum element (considering ascending order) from the unsorted subarray is picked and moved to the sorted subarray.

// C program for implementation of selection sort

#include <stdio.h>

void swap(int *xp, int *yp)

{

    int temp = *xp;

    *xp = *yp;

    *yp = temp;

}

void selectionSort(int arr[], int n)

{

    int i, j, min_idx;

    // One by one move boundary of unsorted subarray

    for (i = 0; i < n-1; i++)

    {

        // Find the minimum element in unsorted array

        min_idx = i;

        for (j = i+1; j < n; j++)

          if (arr[j] < arr[min_idx])

            min_idx = j;

        // Swap the found minimum element with the first element

        swap(&arr[min_idx], &arr[i]);

    }

}

/* Function to print an array */

void printArray(int arr[], int size)

{

    int i;

    for (i=0; i < size; i++)

        printf("%d ", arr[i]);

    printf("\n");

}

// Driver program to test above functions

int main()

{

    int arr[] = {64, 25, 12, 22, 11};

    int n = sizeof(arr)/sizeof(arr[0]);

    selectionSort(arr, n);

    printf("Sorted array: \n");

    printArray(arr, n);

    return 0;

}

Output:

Sorted array:

11 12 22 25 64

Example:

arr[] = 64 25 12 22 11

// Find the minimum element in arr[0...4]

// and place it at beginning

11 25 12 22 64

// Find the minimum element in arr[1...4]

// and place it at beginning of arr[1...4]

11 12 25 22 64

// Find the minimum element in arr[2...4]

// and place it at beginning of arr[2...4]

11 12 22 25 64

// Find the minimum element in arr[3...4]

// and place it at beginning of arr[3...4]

11 12 22 25 64