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The height of a tree is defined as the number of edges on the longest path in the tree. The function shown in the pseudo-code below is invoked as height (root) to compute the height of a binary tree rooted at the tree pointer root.

The appropriate expressions for the two boxes B1 and B2 are:

1. B1: $(1+\text{height}(n \to \text{ right}))$; B2: $(1+\max(h1, h2))$
2. B1: $(\text{height}(n \to \text{ right}))$ ; B2: $(1+\max(h1,h2))$
3. B1: $\text{height}(n \to \text{ right})$ ; B2: $\max(h1, h2)$
4. B1: $(1+ \text{height}(n \to \text{ right}))$ ; B2: $\max(h1, h2)$
edited | 1.9k views

From the diagram below we are able to see how this works :

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is that 1 is added for the root node ?if not plz explain @ arjun sir
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this is a great explanation @amarVashisth

I got a hint ; How to quickly approach this type of question :--In this type of questions where we already know we want to find something(i.e. Height ) then simply draw min possible tree which reach us upto the Given Boxes.

For Box1,Box2  tree will be as given in below img :-->

Now Analyse the code for above trees we get Option A as Ans.

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1st if condition is true only if there is no node in binary tree.

2nd if condition told if there is only 1 node in the tree.Then height of tree is 0.

Now,

if the tree has at least one left node, then it is going to calculate B2

otherwise, if the tree has  only right subtree, tree height calculated by B1 only

B1= right subtree+1 to get height of the tree

Now, h1= height of right subtree of a node

h2= height of left subtree of a node

height of a tree= 1+ max(h1,h2)

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Why added '1' in th final calculation, can't understand!
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h1 is height of left subtree and h2 height of right subtree.

Now, to get total height of tree we have to add root with max (left subtree, right subtree) of the tree.

got it?

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Actually

if u take 3 node tree(as shown in @Rajesh answer h1 and h2 returning 0, So, there to get height we have to take 1+max(h1,h2)=1+0=1)
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Leaf node is taken as at zero height therefore addition of one will be there to make height one