public class Solution {    Dictionary
     
       dic = new Dictionary
      
       ();        public IList
       
         FindDuplicates(int[] nums)        {            var list = new List
        
         ();            foreach (var n in nums)            {                if (!dic.ContainsKey(n))                {                    dic.Add(n, 1);                }                else                {                    list.Add(n);                }            }            return list;        }}