Counting right children of a node in binary tree representation of ordered tree

Question

I need help with this problem. Example tree:

I have a binary tree that represents ordered tree and I have to count the number of children for each node and place that number in corresponding node.

There are three children(B,C,D) for A and three(E,F,G) for D. Zero children for B,C,E,F,G.

Every node only can have two children in physical (binary) representation. If a node has a left child then every right child from this node on is considered a child too. In my example A left child is B. B has one right child C. C has one right child D. So B, C and D are children for A in this task..

At the end of the program the data in nodes should be A(3),B(0),C(0),D(3),E(0),F(0),G(0).

A binary tree by definition cannot have more than 2 children per node. What are you asking? We know nothing about what the format of the input is. — Rob Volgman, Jun 11 '13 at 19:05
If a node has a left child then its children are this left child and all the nodes going right from this left child. — VOid, Jun 11 '13 at 19:11
Every node only can have two children in physical representation. If a node has a left child then every right child from this node on is considered a child too. In my example A left child is B. B has one right child C. C has one right child D. So B, C and D are children for A in this task... — VOid, Jun 11 '13 at 19:16

score 0 · Accepted Answer · answered Jun 11 '13 at 19:29

What you are describing seems like an arbitrary-arity tree represented in a left-child right-sibling pattern. Each node holds a pointer to its left-most child as well as its right sibling.

Finding how many children a given node has shouldn't be too difficult. Just take the left-most child and then count how many times you can iterate to its right sibling. In pseudocode it would look something like this:

def Node {
    Node* left_child
    Node* right_sibling
}

numChildren(Node n) {
    num = 0
    next = n.left_child
    while (next exists)
        num = num + 1
        next = next.right_sibling
    return num
}

Counting right children of a node in binary tree representation of ordered tree

1 Answers1