Build A Binary Tree II - codepath/compsci_guides GitHub Wiki

Unit 8 Session 1 (Click for link to problem statements)

Problem Highlights

• 💡 Difficulty: Easy
• ⏰ Time to complete: 5 mins
• 🛠️ Topics: Trees, Binary Trees

1: U-nderstand

Understand what the interviewer is asking for by using test cases and questions about the problem.

• Established a set (2-3) of test cases to verify their own solution later.
• Established a set (1-2) of edge cases to verify their solution handles complexities.
• Have fully understood the problem and have no clarifying questions.
• Have you verified any Time/Space Constraints for this problem?

2: M-atch

Match what this problem looks like to known categories of problems, e.g. Linked List or Dynamic Programming, and strategies or patterns in those categories.

This is a basic tree construction problem, typically used as a foundation for more complex tree manipulations or traversals.

3: P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Create nodes and assign them as children to form the specified binary tree structure.

1) Create the root node with value 5.
2) Create a left child node with value 10 and assign to root.
3) Create a right child node with value 20 and assign to root.

⚠️ Common Mistakes

• Incorrect assignment of children, which could lead to an incorrect tree structure.

4: I-mplement

Implement the code to solve the algorithm.

root = TreeNode(5)
root.left = TreeNode(10)
root.right = TreeNode(20)

5: R-eview

Review the code by running specific example(s) and recording values (watchlist) of your code's variables along the way.

• Check the structure of the tree to ensure that nodes are connected as expected.

6: E-valuate

Evaluate the performance of your algorithm and state any strong/weak or future potential work.

• Time Complexity: O(1) because the creation and connection of nodes are fixed and do not depend on any input size.
• Space Complexity: O(1) because a constant amount of space is used irrespective of input.