← Return

222. Count Complete Tree Nodes^Easy

Given the root of a complete binary tree, return the number of the nodes in the tree.

According to Wikipedia, every level, except possibly the last, is completely filled in a complete binary tree, and all nodes in the last level are as far left as possible. It can have between 1 and 2h nodes inclusive at the last level h.

Design an algorithm that runs in less than O(n) time complexity.

• Problem
• Solutions
  • Groovy
  • Java
  • JavaScript
  • Kotlin
  • Python
  • TypeScript