Maximum Depth of Binary Tree

Trees · DFS · A node asks its children a smaller question · Easy · about 18 min

Why it matters

Tree recursion is one pattern, not dozens of unrelated tree tricks.

How it connects

Recursion now has a shape: every tree node delegates the same question to its children.

Try first

What depth should an empty tree have? How does a parent use its two child answers?

Interview cue

Depth-first recursion visits each node once, using call-stack space proportional to height.