数组中只出现一次的两个数字

y总的方法学不来，只会这么简简单单粗暴的方法，哭

class Solution {
    public int[] findNumsAppearOnce(int[] nums) {
        HashMap<Integer, Integer> hashMap = new HashMap<>();
        int[] res = new int[2];
        int i = 0;
        for (int x : nums) {
            hashMap.put(x, hashMap.getOrDefault(x, 0) + 1);
        }
        for (Map.Entry<Integer, Integer> e : hashMap.entrySet()) {
            if (e.getValue() == 1)
                res[i++] = e.getKey();
        }
        return res;
    }
}