Compare Binary Trees at Matching Structural Positions
Company: Amazon
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Other
### Problem
Determine whether the binary trees rooted at `p` and `q` have exactly the same structure and the same value at every corresponding node. Left and right child positions are distinct: moving a node from one side to the other does not preserve the tree.
The supplied `TreeNode` has `val`, `left`, and `right` fields:
```cpp
bool isSameTree(TreeNode* p, TreeNode* q);
```
Examples use level-order displays with `null` for absent children; the arguments are tree pointers.
### Examples
```text
Input: p = [4,2,6], q = [4,2,6]
Output: true
```
```text
Input: p = [7,3], q = [7,null,3]
Output: false
```
The second pair has the same visible values but different child positions.
### Constraints
- Each tree has between 0 and 100 nodes.
- Every node value is between -10000 and 10000, inclusive.
- Compare both structure and values, including missing-child positions.
Overview: Compare two binary trees for identical child structure and corresponding values, including null positions.
