Puzzle : finding out repeated element in an Array

Question

Size of an array is n.All elements in the array are distinct in the range of [0 , n-1] except two elements.Find out repeated element without using extra temporary array with con

Answer 1

This example could be useful for int, char, and string.

char[] ch = { 'A', 'B', 'C', 'D', 'F', 'A', 'B' };
Dictionary result = new Dictionary();
foreach (char c in ch)
{
   if (result.Keys.Contains(c))
   {
       result[c] = result[c] + 1;
   }
   else
   {
       result.Add(c, 1);
   }
}
foreach (KeyValuePair pair in result)
{
   if (pair.Value > 1)
   {
       Console.WriteLine(pair.Key);
   }
}
Console.Read();