Trees - Same Tree

Determine if two binary trees are identical (same structure and values).

Input: p=[1,2,3], q=[1,2,3] → Output: true

Input: p=[1,2], q=[1,null,2] → Output: false

Recursive DFS: compare root values, then recursively check left and right subtrees.

If both null return true
If one null or values differ return false
Recursively check left and right subtrees

public boolean isSameTree(TreeNode p, TreeNode q) { if (p == null && q == null) return true; if (p == null || q == null || p.val != q.val) return false; return isSameTree(p.left, q.left) && isSameTree(p.right, q.right); }

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