[leetcode] 349. Intersection of Two Arrays 解题报告

Posted 2020-08-06

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.

第一想法用HashMap<Integer, Boolean>，但错误，用两个HashSet<Ingeger>

一刷：

    public int[] intersection(int[] nums1, int[] nums2) {
        Set<Integer> set1 = new HashSet<Integer>();
        Set<Integer> set = new HashSet<Integer>();
         for (int i = 0; i < nums1.length ; i++) {
            set1.add(nums1[i]);
        }
        for (int i = 0; i < nums2.length; i++) {
            if(set1.contains(nums2[i])){
                set.add(nums2[i]);
            }
        }
        int[] result = new int[set.size()];
        int j=0;
        for (Integer num : set
             ) {
            result[j] = num;
            j++;
        }
        return result;
    }