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The number of configurations of a zig-zag join tree that can be formed when the order of leaves matters.

1. 2n−1
 
2. (2n−2)!2n−1(n−1)!
 
3. 2n−2
 
4. (2n−2)!n!(n−1)!
in Databases 277 views

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answer is d

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