Java: Selection Sort Algorithm

Last update on December 21 2024 09:42:46 (UTC/GMT +8 hours)

Write a Java program to sort an array of given integers using the Selection Sort Algorithm.

Wikipedia says "In computer science, selection sort is a sorting algorithm, specifically an in-place comparison sort. It has O(n2) time complexity, making it inefficient on large lists, and generally performs less efficiently than the similar insertion sort".

Note:
a) To find maximum of elements
b) To swap two elements

Pictorial presentation - Selection search algorithm :

Sample Solution:

Java Code:

import  java.util.Arrays;
  public class  SelectionSort {
  public static void sort(int[] nums)
  {
  for(int currentPlace = 0;currentPlace<nums.length-1;currentPlace++){
  int smallest =  Integer.MAX_VALUE;
  int smallestAt =  currentPlace+1;
  for(int check =  currentPlace; check<nums.length;check++){
  if(nums[check]<smallest){
  smallestAt  = check;
  smallest  = nums[check];
  }
  }
  int temp =  nums[currentPlace];
  nums[currentPlace]  = nums[smallestAt];
  nums[smallestAt]  = temp;
  }
  }
  // Method to test above
  public static void main(String args[])
  {
  SelectionSort ob = new SelectionSort();
  int nums[] = {7, -5, 3, 2, 1, 0, 45};
  System.out.println("Original  Array:");
  System.out.println(Arrays.toString(nums));
  ob.sort(nums);
  System.out.println("Sorted  Array:");
  System.out.println(Arrays.toString(nums));
  }        
  }
  

Sample Output:

Original  Array:
[7, -5, 3, 2, 1, 0, 45]
Sorted  Array:
[-5, 0, 1, 2, 3, 7, 45]

Flowchart:

Java Code Editor:

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