Question

C++

Write a function, singleParent, that returns the number of nodes in a binary tree that have only one child. Add this function to the class binaryTreeType and create a program to test this function. (Note: First create a binary search tree.)

Answer 1

// assuming Node is the class to define a node

int singleParent()

{

    return singleParentUtil(this->root);

}

int singleParentUtil(Node *r)

{

    // if the tree is not empty

    if( r != NULL )

    {

        // calculate the no of such node in the left subtree

        int l = singleParentUtil(root->left);

       

        // calculate the no of such node in the right subtree

        int r = singleParentUtil(root->right);

       

        // if the current node has only 1 node

        if( ( r->left == NULL && r->right != NULL ) || ( r->left == NULL && r->right == NULL ) )

            return 1 + l + r;

        else

            return l + r;

    }

    // if the tree is empty

    else

        return 0;

}