How can I pair socks from a pile efficiently?

Question

Yesterday I was pairing the socks from the clean laundry and figured out the way I was doing it is not very efficient. I was doing a naive search — picking one sock and

Answer 1

List UnSearchedSocks = getAllSocks();
List UnMatchedSocks = new list();
List PairedSocks = new list();

foreach (Sock newSock in UnsearchedSocks)
{
  Sock MatchedSock = null;
  foreach(Sock UnmatchedSock in UnmatchedSocks)
  {
    if (UnmatchedSock.isPairOf(newSock))
    {
      MatchedSock = UnmatchedSock;
      break;
    }
  }
  if (MatchedSock != null)
  {
    UnmatchedSocks.remove(MatchedSock);
    PairedSocks.Add(new PairOfSocks(MatchedSock, NewSock));
  }
  else
  {
    UnmatchedSocks.Add(NewSock);
  }
}