349.md

class Solution {
    public int[] intersection(int[] nums1, int[] nums2) {
       return hashMethod(nums1, nums2);
  }

  private static int[] hashMethod(int[] nums1, int[] nums2) {
    HashSet<Integer> set1 = new HashSet<Integer>();
    for (int i = 0; i < nums1.length; i++) {
      set1.add(nums1[i]);
    }
    
    HashSet<Integer> set2 = new HashSet<Integer>();
    for (int i = 0; i < nums2.length; i++) {
      set2.add(nums2[i]);
    }
    
    if (set1.size() <= set2.size()) {
      return getInts(set1, set2);
    } else {
      return getInts(set2, set1);
    }
  }
   private static int[] getInts(HashSet<Integer> smallset, HashSet<Integer> bigset) {
       int[] ints = new int[smallset.size()];
    int s = 0;
    for (Integer i : smallset) {
      if (bigset.contains(i)) {
        ints[s++] = i;
      }
    }
    return Arrays.copyOf(ints,s);
  }
}