Same Tree

Validate Binary Search Tree

Invert Binary Tree

Determine whether two binary trees have identical structure and values.

Return true when binary trees `p` and `q` have the same structure and equal values.

## Example
```json
Input: {"p":[1,2,3],"q":[1,2,3]}
Output: true
```

## Constraints
- 0 <= total nodes <= 2000
- -10000 <= node value <= 10000

## Follow-up
How would an iterative queue-based comparison work?

The key pattern is: Parallel DFS compares corresponding nodes. Identify the state and invariant before coding.

Recognize the Pattern

Advance one state transition at a time. Mark or update state before exploring dependent work.

Build the Algorithm

Test empty or minimal input, skewed shapes, duplicates where allowed, and impossible outcomes.

Check Edge Cases

Time: O(n). Space: O(h).

Java/Go/Rust below are reference solutions for learning the pattern in those languages; only Python and JavaScript can be run and submitted for this problem, since the remote judge doesn't support the TreeNode structure yet.