55. Binary Tree Right Side View

A large-scale visualization system renders hierarchical data such as:

• UI component trees
• file systems
• service dependency graphs

To improve clarity in dashboards, the system provides a “right-side projection” view of the tree — showing only the nodes visible when the structure is observed from the right side.

This is useful for:

• summarizing deep hierarchies
• monitoring layered systems
• visualizing dominant nodes at each level

The system receives a binary tree and must return the list of nodes visible from the right side, ordered from top to bottom.

This is a common coding interview problem frequently asked in Google, Amazon, Netflix, Meta, Apple, Microsoft, Uber, and Bloomberg interviews.

Your Task

Given the root of a binary tree, return a list of values of the nodes you can see from the right side.

Input Format

• root: root node of a binary tree

Each node:

TreeNode { int val; TreeNode left; TreeNode right;}

Output Format

• A list/array of integers representing visible nodes from right view

Examples

Constraints

• 0 ≤ number of nodes ≤ 100,000
• -10^9 ≤ Node.val ≤ 10^9