programming-for-dummies

Taking Action on Trees 389
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Removing a sub-tree can leave
remaining nodes disconnected from
the rest of the tree.
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Figure 5-14:
Pruning
a tree
removes
two or more
nodes from
a tree.
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8
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or 4
9
The computer might use a tree data structure to represent all possible
moves when the root node represents one possible move. Then each alternating
level in the tree represents the possible human responses and the
best possible computer responses, as shown in Figure 5-16.
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Book III
Chapter 5
Graphs and Trees
By organizing possible moves in a tree, a computer can determine the best
possible move to make that will give its human opponent the worst possible
moves later. This strategy is min-max — the computer minimizes the
human’s best possible moves and maximizes its own best moves.
Despite having to create trees out of other data structures (such as linked
lists) and being more complicated to create and manage than other data
structures, trees are one of the most useful and flexible data structures
available.