public static void main(String args[]){
        int arr[] = {1,2,3,11,2,5,6};
        DuplicateWithinkIndices dk = new DuplicateWithinkIndices();
        System.out.println(dk.duplicate(arr, 3));
    }
Write a function that determines whether a array contains duplicate 
characters within k indices of each other
src/com/interview/array/DuplicateWithinkIndices.java