数组中数字出现的次数

class Solution {
    public int[] singleNumbers(int[] nums) {
    Set<Integer> set = new HashSet<>();
    int n = nums.length;
    for(int i=0;i<n;i++){
        if(set.contains(nums[i])){
            set.remove(nums[i]);
        }else{
            set.add(nums[i]);
        }
    }
   
    Iterator<Integer> it = set.iterator();
    
    return new int[]{it.next(),it.next()};
    }
}