Subset_Sum

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

class Program

{

   static int n;
   static int max;
   static int[] set;
   static List<int> subset;
   static byte[] binary;
   static int flag;
   static void Main()
   {
      max = int.Parse(Console.ReadLine());
      set = Console.ReadLine().Split(' ').Select(p => int.Parse(p)).Distinct().ToArray();
      n = set.Length;
      subset = new List<int>(n);
      binary = new byte[n];
      flag=0;
      int size = 2 << (n - 1);
      for(int i = 0; i < size; i++)
      {
          if(i!=0)
            Printsubset();
          BinaryIncrement();
      }
       if(flag==0)
           Console.WriteLine("No matching subsets");
   }
   static void BinaryIncrement()
   {
       for (int i = n - 1; i >= 0; i--)
       {
           if (binary[i] == 0)
           {
               binary[i] = 1;
               return;
           }
           binary[i] = 0;
       }
   }
   static void Printsubset()
   {
      subset.Clear();
      for(int i = n - 1; i >= 0; i--)
      {
         if (binary[i] == 1)
             subset.Add(set[n - 1 - i]);
      }
      if (subset.Sum() == max)
      {
          Console.WriteLine(String.Join(" + ", subset));
          flag = 1;
      }
   }
}