Delete duplicate rows from two dimentsional array

Question

Let\'s say I have two dimensional array that represents simple matrix

int[,] matrix= new int[,] { { 1, 2 }, { 3, 4 }, { 1, 2 }, { 7, 8 } };

Answer 1

int[,] list = new int[,] { { 1, 2 }, { 3, 4 }, { 1, 2 }, { 7, 8 } };            
  List> newList = new List>();

   bool dupFound;

       for (int i = 0; i < list.Length; i++)
       {
         dupFound = false;

         for (int a = 0; a < list.Length; i++)
          {
           if ((i != a) && list[a, 0] == list[i, 0] && list[a, 1] == list[i, 1])
           {
              dupFound = true;
             break;
                   }
            }

               if (!dupFound)
                {
                    var nonDup = new KeyValuePair(list[i,0], list[i,1]);
                    newList.Add(nonDup);
                }
            }