import java.util.*;

/*

* Given two arrays, write a function to compute their intersection.

* Example:

* Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2].

* Note:

Each element in the result must be unique.

The result can be in any order.

*/

public class intersection {

public static int[] intersection(int[] nums1, int[] nums2) {

if (nums1 == null || nums2 == null) return null;

Set<Integer> array = new HashSet<Integer>();

Set<Integer> common = new HashSet<Integer>();

for (int i = 0; i < nums1.length; i++) {

array.add(nums1[i]);

}

for (int j = 0; j < nums2.length; j++) {

if (array.contains(nums2[j])) {

common.add(nums2[j]);

}

}

int[] result = new int[common.size()];

int k = 0;

for (int integer : common) {

result[k] = integer;

k += 1;

}

return result;

}

public static int[] findCommon (int[] s, int[] l) {

Set<Integer> sArray = new HashSet<Integer>();

Set<Integer> common = new HashSet<Integer>();

for (int i = 0; i < s.length; i++) {

sArray.add(s[i]);

}

for (int j = 0; j < l.length; j++) {

if (sArray.contains(l[j])) {

common.add(l[j]);

}

}

int[] result = new int[common.size()];

int k = 0;

for (int integer : common) {

result[k] = integer;

k += 1;

}

return result;

}

public static void main(String[] args) {

int[] a = {1, 2, 2, 15, 3};

int[] b = {2, 5, 7, 15, 1};

int[] res = intersection(a, b);

for (int i = 0; i < res.length; i++) {

System.out.print(" " + res[i]);

}

}

}