Selection Sort

Selection sort is a straightforward sorting algorithm. This sorting method is an in-place comparison-based algorithm that divides the list into two halves, the sorted part on the left end and the unsorted part on the right. Initially, the sorted section is empty, while the unsorted section contains the complete list.

The smallest element from the unsorted array is chosen and swapped with the leftmost element, and that element is added to the sorted array. This operation is repeated until the unsorted array boundary is moved 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

Pseudocode

procedure selection sort 
   list  : array of items
   n     : size of list

   for i = 1 to n - 1
   /* set current element as minimum*/
      min = i    
  
      /* check the element to be minimum */

      for j = i+1 to n 
         if list[j] < list[min] then
            min = j;
         end if
      end for

      /* swap the minimum element with the current element*/
      if indexMin != i  then
         swap list[min] and list[i]
      end if
   end for
	
end procedure