Java Program for Insertion Sort

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.

Algorithm of Insertion Sort

The algorithm of Insertion Sort is mentioned below:

1. Variable declared i=1
2. 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.
3. Return the Sorted Array.

Program of Insertion Sort Java

Java

// Java program for implementation of Insertion Sort
class InsertionSort {
    // Function to sort array using insertion sort
    void sort(int arr[])
    {
        int n = arr.length;
        for (int i = 1; i < n; ++i) {
            int key = arr[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 && arr[j] > key) {
                arr[j + 1] = arr[j];
                j = j - 1;
            }
            arr[j + 1] = key;
        }
    }

    // A utility function to print array of size n
    static void printArray(int arr[])
    {
        int n = arr.length;
        for (int i = 0; i < n; ++i)
            System.out.print(arr[i] + " ");

        System.out.println();
    }

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

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

        printArray(arr);
    }
}

Output

5 6 11 12 13 

The complexity of the above method

Time Complexity: O(N^2) 
Auxiliary Space: O(1)

Reference

Please refer complete article on Insertion Sort for more details!