In a tournament tree (also called a selection tree), each external node represents a player and each internal node represents the winner of the match played between the players represented by its children nodes. These tournament trees are also called winner trees because they are being used to record the winner at each level. We can also have a loser tree that records the loser at each level.
Consider the tournament tree given in Fig. 9.14. There are 8 players in total whose names are represented using a, b, c, d, e, f, g, and h. In round 1, a and b; c and d; e and f; and finally g and h play against each other. In round 2, the winners of round 1, that is, a, d, e, and g play against each other. In round 3, the winners of round 2, a and e play against each other. Whosoever wins is declared the winner. In the tree, the root node a specifies the winner.