Top Trading Cycle algorithm

4. Wulfstan gave his children Pokemon cards for Christmas. To teach them about the value of trade, he gave each of them their least favourite Pokemon on purpose. Ben got a Bidoof (B), Eve got an Exeggutor {E}, Guy got a Garbodor (G), Lee got a Luvdisc (L), Meg got a Magikarp (M), Sue got a Slowbro {S} and Tom got a Trapinch (1'). Seeing the expected disappointment in their eyes, Wulfstan tried to cheer them up by pointing out that there is scope for mutually beneficial exchanges. Sue fetched a book on algorithmic mechanism design she got on her birthday and convinced her siblings that they should use the Top Trading Cycle (TTC) algorithm to reallocate the cards. They all wrote down their preferences on a piece of paper: Ben Eve Guy Lee Meg Sue Tom L B B S T E S T G M T G L G M S S L B B E G T T B T G B B E G L M S T Use the TTC algorithm to find out which card each of them would receive