Instructions
User Manual:
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Page Count: 2
Binary Search Tree :
Lowest Common
Ancestor
You are given pointer to the root of the binary search tree and two values and . You need to return
the lowest common ancestor (LCA) of and in the binary search tree.
In the diagram above, the lowest common ancestor of the nodes and is the node . Node is the
lowest node which has nodes and as descendants.
Function Description
Complete the function
lca
in the editor below. It should return a pointer to the lowest common ancestor
node of the two values given.
lca has the following parameters:
- root: a pointer to the root node of a binary search tree
- v1: a node.data value
- v2: a node.data value
Input Format
The first line contains an integer, , the number of nodes in the tree.
The second line contains space-separated integers representing values.
The third line contains two space-separated integers, and .
To use the test data, you will have to create the binary search tree yourself. Here on the platform, the
tree will be created for you.
Constraints
The tree will contain nodes with
data
equal to and .
Output Format
Return the a pointer to the node that is the lowest common ancestor of and .
Sample Input
and .
Sample Output
[reference to node 4]
Explanation
LCA of and is , the root in this case.
Return a pointer to the node.
