Dsa
Trees
Easy
Binary Tree Leaf Counter
You are given the root of a binary tree. Write a function to count the number of leaf nodes in the tree. A leaf node is a node that does not have any children. The input tree is given in a serialized format where each node value is separated by a space, and 'null' represents a nonexistent node. The first value in the input represents the root of the tree.
Example:
Input:
1 2 3 null null 4 5
Output:
3
Key concepts
treesrecursioncounting
Practise this out loud — free
Start a mock interview on THIS exact question — a voice AI interviewer opens with it, pushes back like a real onsite, then hands you an instant scorecard.
🎙 Practise this question now