leetcode 349. Intersection of Two Arrays

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.

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思考：求两个数组的交集， 要求去重；

public class Solution {
    public int[] intersection(int[] nums1, int[] nums2) {
        Set<Integer> countSet = new HashSet<>();
        Set<Integer> finalSet = new HashSet<>();
        for(int num : nums1){
            countSet.add(num);
        }
        for(int num : nums2){
            if(countSet.contains(num)){
                finalSet.add(num);
            }
        }
        int[] ret = new int[finalSet.size()];
        int i = 0;
        for(int num : finalSet){
            ret[i++] = num;
        }
        return ret;
    }
}