question

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

Example 1:

Input: nums1 = [1,2,2,1], nums2 = [2,2]
Output: [2]
Example 2:

Input: nums1 = [4,9,5], nums2 = [9,4,9,8,4]
Output: [9,4]
Note:

Each element in the result must be unique.
The result can be in any order.

Ideas

1.set去重
2.hash表

class Solution {
    public int[] intersection(int[] nums1, int[] nums2) {
        
          int[] less=nums1.length<nums2.length?nums1:nums2;
            int[] more=nums1.length>nums2.length?nums1:nums2 ;
            HashSet<Integer> lessSet =new HashSet<Integer>();
            for (int i = 0; i <less.length ; i++) {
                lessSet.add(less[i]);
            }           
            HashSet<Integer> moreSet =new HashSet<Integer>();
            for(int i=0 ;i<more.length;i++){
                if(lessSet.contains(more[i])){
                    moreSet.add(more[i]);
                }
            }
            //Set 转为 数组
            int size = moreSet.size(), k = 0;
            int[] ans = new int[size];
            for(int n : moreSet){
                ans[k++] = n;
            }
            return ans;       
    }
}