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Ancestors in Binary Tree
Submissions: 23033   Accuracy:

39.92%

  Difficulty: Easy   Marks: 2
Associated Course(s):   Amazon SDE Test Series

Given a Binary Tree and a target key, you need to find all the ancestors of the given target key.

              1
            /   \
          2      3
        /  \
      4     5
     /
    7
Key: 7
Ancestor: 4 2 1

Example 1:

Input:
        1
      /   \
     2     3
target = 2
Output: 1

Example 2:

Input:
         1
       /   \
      2     3
    /  \   /  \
   4    5 6    8
  /
 7
target = 7
Output: 4 2 1

 

Your Task:
Your task is to complete the function Ancestors() that finds all the ancestors of the key in the given binary tree.
Note:
The return type is
cpp: vector<int>
Java: ArrayList<Integer>
python: list

Expected Time Complexity: O(N).
Expected Auxiliary Space: O(H).
Note: H is the height of the tree and this space is used implicitly for recursion stack.

Constraints:
1 <= N <= 1000
1<= data of node <= 10000

Note: The Input/Output format and Examples given are used for the system's internal purpose, and should be used by a user for Expected Output only. As it is a function problem, hence a user should not read any input from stdin/console. The task is to complete the function specified, and not to write the full code.

** For More Input/Output Examples Use 'Expected Output' option **

Contributor: Tanmay Agrawal
Author: harshitsidhwa


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