The selection sorting algorithm is one of the simplest sorting algorithms: it divides input into two parts and builds a sorted part from the left as it passes through the unsorted part of the array. With each iteration sorted part increases, while the unsorted part decreases by one element.
Selection sort is an in-place comparison based sorting algorithm. Its time complexity is O(n2), while it is space complexity is O(n).
Please see below the implementation in Java:
import java.util.Arrays;
public class SelectionSort {
public static void main(String []args){
char[] arr = {'H','S','A','F','R','P','E','C','Z','W','G','J','B','Q','L'};
System.out.println("Input array: " + Arrays.toString(arr));
sort(arr, arr.length);
System.out.println("Sorted array: " + Arrays.toString(arr));
}
private static void sort(char arr[], int n) {
// Make sure n is not greater than the length of the array.
// Otherwise set it to length to avoid overindexing the array.
if (n > arr.length) {
n = arr.length;
}
for (int i = 0; i < n-1; i++) {
// Find the minimum element in unsorted array.
int min_index = i;
for (int j = i+1; j < n; j++) {
if (arr[j] < arr[min_index]) {
min_index = j;
}
}
// Swap the minimum element with the first element.
char temp = arr[min_index];
arr[min_index] = arr[i];
arr[i] = temp;
}
}
}
The output of the application:
Input array: [H, S, A, F, R, P, E, C, Z, W, G, J, B, Q, L]
Sorted array: [A, B, C, E, F, G, H, J, L, P, Q, R, S, W, Z]
Istvan S.
tutor
The class is actually public (i.e. "public class SelectionSort"), the sort method is private (i.e. private static void sort..). You can always make the sort method public if you want to access it from outside of this class.
My example followed the Java naming rules and conventions:
https://docs.oracle.com/javase/tutorial/java/nutsandbolts/variables.html
Based on the naming convention the method and variable names are written using camel case, so instead of "selectionsort", the method name should be written as "selectionSort" and they should start with lowercase letter, therefore my example used "arr" instead "Arr" and "n" instead of "N". (The code will work with the original names from the question though as long as you change all the references in the implementation accordingly).
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05/12/20
Ashley P.
Could you tell me why you used a private class particularly? Can I instated use a public class? And the question says to write a function in the form selectionsort(Arr, N). But java won't let you use that exact format for parameters where we define the method. Instead is it incorrect if I define parameters the way you've defined it?05/12/20