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.
Example 1:
1
/ \
2 3
\ \
5 4
Input: root = [1,2,3,null,5,null,4]
Output: [1,3,4]
Explanation: From the right side, you see nodes 1, 3, and 4.
Example 2:
1
\
3
Input: root = [1,null,3]
Output: [1,3]
Example 3:
Input: root = []
Output: []
Examples
Example 1
Input: root = [1,2,3,null,5,null,4]
Output: [1,3,4]
Explanation: At level 0, the rightmost node is 1. At level 1, the rightmost node is 3. At level 2, the rightmost node is 4.
Example 2
Input: root = [1,null,3]
Output: [1,3]
Explanation: At level 0, the rightmost node is 1. At level 1, the rightmost node is 3.
Example 3
Input: root = []
Output: []
Explanation: An empty tree has no visible nodes from any side.
Constraints
- -The number of nodes in the tree is in the range [0, 100].
- --100 <= Node.val <= 100
Optimal Complexity
Time
O(n)
Space
O(n)
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