Boundary Traversal of Binary Tree

Contributed by
Prashansa
Last Updated: 23 Feb, 2023
Hard
0/120
Avg time to solve 20 mins
Success Rate 85 %
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Problem Statement

You have been given a binary tree of integers. Your task is to print the boundary nodes of this binary tree in Anti-Clockwise direction starting from the root node.

NOTE:
``````The boundary nodes of a binary tree include nodes from the left boundary, right boundary and the leaf nodes without duplicate nodes. However, the values from the nodes may contain duplicates.
``````
For Example:

Detailed explanation ( Input/output format, Notes, Images )
Constraints:
``````1 <= T <= 10^2
1 <= N <= 2^12

Where 'N' is the total number of nodes in the binary tree.

Time Limit: 1 sec
``````
Sample Input 1:
``````2
1 2 3 4 -1 5 -1 -1 -1 -1 -1
1 2 -1 3 -1 4 -1 -1 -1
``````
Sample Output 1:
``````1 2 4 5 3
1 2 3 4
``````
Explanation of Sample Input 1:
``````For the first test case, we have 1 as the root node. 2, 4 as left boundary nodes. 3, 5 as the right boundary nodes. We don't have any leaf nodes.

For the second test case, we have 1 as the root node. 2, 3 as the left boundary nodes and 4 as a leaf node. We don't have any right boundaries.
``````
Sample Input 2:
``````1
1 2 3 4 5 6 7 -1 -1 -1 -1 -1 -1 -1 -1
``````
Sample Output 2:
``````1 2 4 5 6 7 3
``````
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