Java Program for Insertion Sort

Last Updated : 22 Oct, 2024

Insertion sort is a simple sorting algorithm that works the way we sort playing cards in our hands. In this article, we will write the program on Insertion Sort in Java.

Please refer complete article on Insertion Sort for more details!

Algorithm of Insertion Sort

The algorithm of Insertion Sort is mentioned below:

Variable declared i=1
Traverse the Array till i<N
If arr[i]<arr[i-1] then arr[j]=value present after shifting the elements of the array from j to i-1.
Return the Sorted Array.

Program of Insertion Sort Java

Below is the implementation of Insertion Sort in Java:

// Java program for implementation of Insertion Sort

class InsertionSort {
  
    // Function to sort array using insertion sort
    void sort(int a[])
    {
        int n = a.length;
        for (int i = 1; i < n; ++i) {
            int k = a[i];
            int j = i - 1;

            // Move elements of arr[0..i-1], that are
            // greater than key, to one position ahead
            // of their current position
            while (j >= 0 && a[j] > k) {
                a[j + 1] = a[j];
                j = j - 1;
            }
          
            a[j + 1] = k;
        }
    }

    public static void main(String args[])
    {
        int a[] = { 12, 11, 13, 5, 6 };

        InsertionSort ob = new InsertionSort();
        ob.sort(a);

        int n = a.length;
        for (int i = 0; i < n; ++i)
            System.out.print(a[i] + " ");

    }
}