映射 04 Leetcode中的350号问题

350.两个数组的交集 II

class Solution { 

    public int[] intersect(int[] nums1, int[] nums2) {
        TreeMap<Integer, Integer> map = new TreeMap<>();
        for (int num : nums1) {
            if (!map.containsKey(num)) {
                map.put(num, 1);
            } else {
                map.put(num, map.get(num) + 1);
            }
        }

        ArrayList<Integer> list = new ArrayList<>();
        for (int num : nums2) {
            if (map.containsKey(num)) {
                list.add(num);
                map.put(num, map.get(num) - 1);
                if (map.get(num) == 0) {
                    map.remove(num);
                }
            }
        }

        int[] res = new int[list.size()];
        for (int i = 0; i < res.length; i++) {
            res[i] = list.get(i);
        }
        return res;
    }

}