Same Binary Tree
Detailed guide and Python implementation for the 'Same Binary Tree' problem.
1. Concept Overview
The 'Same Binary Tree' problem is a key challenge in the Trees section.
This implementation focuses on medium-level logic in Python.
We prioritize technical accuracy and code readability in our provided solutions.
2. Real-World Applications
3. Visual Intuition
Visualizing the logic flow for Same Binary Tree.
4. Prerequisites
5. Step-by-Step Thinking
1. Understand the problem
Read the problem statement for Same Binary Tree carefully.
2. Formulate brute force
Draft a simple iterative solution.
3. Identify inefficiency
Look for redundant calculations.
4. Optimize search path
Use hashing or sorting to speed up the process.
5. Final Implementation
Clean up the code for production standards.
Problem Statement
Given the roots of two binary trees p and q, write a function to check if they are the same or not.
Two binary trees are considered the same if they are structurally identical, and the nodes have the same value.
The trees are represented as level-order lists. Implement a function isSameTree(p: list, q: list) -> bool.
- •The number of nodes in both trees is in the range [0, 100]
- •-10000 <= Node.val <= 10000
Examples
[1,2,3], [1,2,3]
True
Both trees have the same structure and values.
[1,2], [1,None,2]
False
In the first tree, 2 is the left child. In the second tree, 2 is the right child. Different structures.
[1,2,1], [1,1,2]
False
Same structure but different values at the children.
Need a Hint?
Edge Cases to Watch
- Empty input structures
- Single element inputs
- Large numerical bounds
Ready to Solve?
Open the problem in PyRun's browser-based Python editor. Your code runs fully offline — no server required.
Interview Insights & Variations
Complexity Analysis Breakdown
Why Time: Directly evaluates all possibilities.
Why Space: Uses standard local memory.
Why Time: Optimized paths reduce total operations.
Why Space: May trade memory for speed.
Optimized Solution Python Code
Optimized Solution Python Code
def is_same_tree_opt(p, q):
if isinstance(p, list):
r1 = build_tree(p)
r2 = build_tree(q)
return is_same_tree_opt_helper(r1, r2)
return is_same_tree_opt_helper(p, q)
def is_same_tree_opt_helper(p: TreeNode, q: TreeNode) -> bool:
if not p and not q:
return True
if not p or not q or p.val != q.val:
return False
return is_same_tree_opt_helper(p.left, q.left) and is_same_tree_opt_helper(p.right, q.right)Brute Force Code (Spoiler Guarded)
Brute Force Code (Spoiler Guarded)
def is_same_tree_brute(p, q):
if isinstance(p, list):
r1 = build_tree(p)
r2 = build_tree(q)
return is_same_tree_brute_helper(r1, r2)
return is_same_tree_brute_helper(p, q)
def is_same_tree_brute_helper(p: TreeNode, q: TreeNode) -> bool:
def serialize(node):
if not node: return [None]
return [node.val] + serialize(node.left) + serialize(node.right)
return serialize(p) == serialize(q)Algorithm Pattern Checklist
When dealing with Trees data patterns.
Core Prerequisites
Revision Key Notes
Common Mistakes & Pitfalls
Related Questions
Recommended Python Resources
Expand your knowledge with related interactive tutorials, cheat sheets, and code comparisons.
Python Loops
Learn how to use Python loops to iterate over data. Master for loops, while loops, break, continue, and loop best practices with interactive examples.
How to Sort a List in Python
Learn how to sort a list in Python using the sort() method and the sorted() function. Discover custom key sorting and reverse order examples.
Python String Methods
A complete reference guide for Python string manipulation. Master formatting, searching, splitting, replacing, and checking string properties.
Python vs JavaScript: Which Programming Language is Best?
A comprehensive comparison between Python and JavaScript. Explore syntax differences, performance, use cases (backend vs frontend), and coding examples.