public class Solution {    public int[] SingleNumber(int[] nums) {        var dic = new Dictionary
     
      ();            foreach (var num in nums)            {                if (!dic.ContainsKey(num))                {                    dic.Add(num, 1);                }                else                {                    dic[num]++;                }            }            var list = dic.OrderBy(x => x.Value).ToList();            var ary = new int[2];            ary[0] = list[0].Key;            ary[1] = list[1].Key;            return ary;    }}