Multiple choice

What is the total number of possible binary search tree with keys 20, 25 and 5?

  1. 4

  2. 3

  3. 5

  4. 6
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The number of unique binary search trees for n nodes is given by the n-th Catalan number. For n=3, the number of BSTs is C(3) = (1/(3+1)) * binom(6, 3) = 5.

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