using System;
using System.Collections.Generic;
using System.Linq;

class TwoSum
{
        public static Tuple FindTwoSum(IList list, int sum)
        {
            int indexA = 0;
            int indexB = 0;
            Random rand = new Random();
            Tuple result = null;
            var results = new Dictionary();
            		
            foreach (int v in list) //this is the slow way to do it ( iterative nested loops)	
            {
                foreach (int r in list)
                {
                    Console.WriteLine(v + " + " + r + " = " + (v + r));

                    if (v + r == sum)
                    {
                        Console.WriteLine("Hit! indexA: " + indexA + ", indexB: " + indexB);
                        Console.WriteLine();

                        results.Add(indexA, indexB); 
                        break;
                    }

                    indexB++;
                }

                indexA++;
                indexB = 0;
            }

            int i = 0;
            int t = 0;
            
            if(results.Count > 0)
            {
                t = rand.Next(0, (results.Count - 1));    
            }

            Console.WriteLine();
            Console.WriteLine("random: " + t);
            Console.WriteLine("checking Dictionary");
			
            foreach (KeyValuePair pair in results)
            {
                Console.WriteLine(pair.Key + ", " + pair.Value);

                if (i == t)
                {
                    result = new Tuple(pair.Key, pair.Value);
                }

                i++;
            }

            return result;
        }

    public static void Main(string[] args)
    {
        Tuple indices = FindTwoSum(new List() { 3, 1, 5, 7, 5, 9 }, 10);
        if(indices != null) 
        {
            Console.WriteLine(indices.Item1 + " " + indices.Item2);
        }
    }
}