# Data Structure MCQ - Tree

This section focuses on the "Tree" of the Data Structure. These Multiple Choice Questions (mcq) should be practiced to improve the Data Structure skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

1. The no of external nodes in a full binary tree with n internal nodes is?

A. n

B. n+1

C. 2n

D. 2n + 1

View Answer

Ans : B

Explanation: The no of external nodes in a full binary tree with n internal nodes is n+1.

2. Which of the following is a true about Binary Trees?

A. Every binary tree is either complete or full.

B. Every complete binary tree is also a full binary tree.

C. Every full binary tree is also a complete binary tree.

D. No binary tree is both complete and full.

E. None of the above

View Answer

Ans : E

Explanation: A full binary tree (sometimes proper binary tree or 2-tree or strictly binary tree) is a tree in which every node other than the leaves has two children. A complete binary tree is a binary tree in which every level, except possibly the last, is completely filled, and all nodes are as far left as possible. A) is incorrect.

3. A Binary Tree can have

A. Can have 2 children

B. Can have 1 children

C. Can have 0 children

D. All of the above

View Answer

Ans : D

Explanation: A Binary Tree can have 0, 1, 2 children

4.Which of the following is not an advantage of trees?

A. Hierarchical structure

B. Faster search

C. Router algorithms

D. Undo/Redo operations in a notepad

View Answer

Ans : D

Explanation: This is an application of stack.

5.The difference between the external path length and the internal path length of a binary tree with n internal nodes is?

A. 1

B. n

C. n + 1

D. 2n

View Answer

Ans : D

Explanation:The difference between the external path length and the internal path length of a binary tree with n internal nodes is 2n.

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