Right Side View of Binary Tree

Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. Input The root of a binary tree Output A list of node values observed from the right side view Example Input: [1,2,3,null,5,null,4] Output: [1,3,4] Constraints The number of nodes in the tree is in the range [0, 100]. -100 <= Node.val <= 100. Example Input [1,2,3,null,5,null,4]