package me.ramswaroop.arrays;
import java.util.Arrays;
import java.util.HashSet;
/**
* Created by IntelliJ IDEA.
*
* @author: ramswaroop
* @date: 10/18/15
* @time: 8:40 PM
*/
public class DuplicatesInArrayWithinKDistance {
/**
* Finds duplicates in an unsorted array {@param a} which are
* only k distance apart from each other.
*
* @param a
* @param k
* @return
*/
public static int[] findDuplicatesInArrayWithinKDistance(int[] a, int k) {
int index = 0;
int[] duplicates = new int[a.length];
HashSet<Integer> hashSet = new HashSet<>();
for (int i = 0; i < a.length; i++) {
if (hashSet.contains(a[i])) {
duplicates[index++] = a[i];
} else {
hashSet.add(a[i]);
}
if (i >= k) {
hashSet.remove(a[i - k]);
}
}
return Arrays.copyOf(duplicates, index);
}
public static void main(String a[]) {
System.out.println(Arrays.toString(findDuplicatesInArrayWithinKDistance(new int[]{1, 2, 8, 1, 3, 4, 5, 6, 6, 7}, 3)));
}
}