PermutationDemo generates duplicate

[skills-up]

The PermutationDemo.java program will lead to duplicates. A quick fix is to do the inner loop on the clone of the array.

    public static void printPermutn(int[] arr, int index) {
        int len = arr.length;

        if (index == (len-1)) {
            for(int i=0; i<len; i++) System.out.print(arr[i]);
            System.out.println();
        } else {
            int[] a = arr.clone();
            for(int i=index; i<len; i++) {
                int t = a[i];
                a[i] = a[index];
                a[index] = t;
                printPermutn(a, index+1);
            }
        }
    }

[anupamhaldkar]

You can just add swapping one more time after recursive condition so that array becomes original. ⛳