Binary Tree Right Side View

Binary Tree Right Side View

Given the root of 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.

Examples

Example 1:

Input: root = [1, 2, 3, null, 5, null, 4]
Output: [1, 3, 4]

      1
     / \
    2   3
     \   \
      5   4

Example 2:

Input: root = [1, null, 3]
Output: [1, 3]

Example 3:

Input: root = []
Output: []

Constraints

• The number of nodes in the tree is in the range [0, 100].
• -100 <= Node.val <= 100

Expected Complexity

• Time: O(n)
• Space: O(n)