AVL Tree insertion

Question

The tree given is as follows:

 

          40
         /  \
        35   53
       /      \
      20      60

 

How many rotations are required for insertion of elements 30,55,45,65,42 in above tree.
(A) 2
(B) 3
(C) 4
(D) None of these

Comments

3 rotation

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I think none of these

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Counting 2 for double rotations, and 1 for single rotation, how many rotations you needed to create valid AVL tree?

Answer 1

Option D None of these

Comments

u seem to have mistakenly changed 20 to 25 in right rotation after inserting 30. So your count is 5 rotations in total, right?

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yeah sry i did mistake but i got 5 rotations and i will edit it thanks

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How is the last rotation RL ? its unbalanced at node 53 and the inserted node 42 is LEFT child of LEFT subtree . So shouldnt it be a LL rotation?

Answer 2

1st rotation will be LR rotation
2nd will be RL rotation
3rd will be LL rotation

3 rotations will be required....

Comments

S​o each of LR, RL are actually 2 rotations and LL is 1. That means it should be 5 right?

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yes answer is 5 none of these.

Answer 3

Answer is :B] 3 rotations => LR, RL, LL

Answer 4

It requires 3 Rotation which are which are LL and RR and with combination of Lr and RL we will get a total of % rotation.

actually in Question they should give which rotation has to be performed.