Consider the following game tree in which root is a maximizing node and…
2016
Consider the following game tree in which root is a maximizing node and children are visited left to right. What nodes will be pruned by the alpha-beta pruning ?
- A.
I
- B.
HI
- C.
CHI
- D.
GHI
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Correct answer: B
Answer: Nodes H and I are pruned.
Key steps:
Evaluate the left child (a min node with leaves 3, 12, 8): its minimum is 3. The root (max) therefore gets alpha = 3.
Move to the right child (a min node). Visit its first leaf G = 2, so the current minimum at this node is 2.
Compare this minimum (2) with the root's alpha (3). Because 2 <= 3, the right child cannot produce a value that will beat the root's current best, so the remaining siblings (H with 15 and I with 6) are pruned.
Traversal order (visited): A → B → D (3) → E (12) → F (8) → C → G (2). Pruned: H and I.