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.

Solution：

public class Solution 
{
    public int[] intersection(int[] nums1, int[] nums2) 
    {
        Set<Integer> hs = new HashSet<>();
        for(int n : nums1)
        {
            hs.add(n);
        }
        Set<Integer> resultSet = new HashSet<>();
        for(int i : nums2)
        {
            if(hs.contains(i))
                resultSet.add(i);
        }
        int size = resultSet.size();
        int[] result = new int[size];
        int i = 0;
        Iterator itr = resultSet.iterator();
        while(itr.hasNext())
        {
            result[i++] = (int)itr.next();
        }
        return result;
    }
}