350. 两个数组的交集 II Java版

class Solution {
    public int[] intersect(int[] nums1, int[] nums2) {
        Map map = new HashMap<>(nums1.length);

        for(int num:nums1){
            Integer count = map.get(num);
            if(count == null)
                map.put(num,1);
            else
                map.put(num,++count);
        }
        
        List list = new ArrayList<>();

        for(int num:nums2){
            Integer count = map.get(num);
            if(count != null && count != 0){
                list.add(num);
                map.put(num,--count);
            }
        }

        int[] res = new int[list.size()];
        for(int i=0; i