Question

Write a function int levelSearch(Node* root, int key) that takes as input the root node of a Binary Search tree and a key. The function searches the key in the BST and returns the level of the found node. If the key is not found in the tree, return -1. The level starts at 0 for the root node and increases from top to bottom.

We have defined the following node C++ Node class for you:

class Node {
 public:         
      int name; 
      Node* left = NULL;      
      Node* right = NULL; };

Note: In the test cases, the first line for input has multiple nodes and we will be inserting each one of them in your tree using an insert function. The second line is the key to be searched. The output is the level of the key in the BST.

Sample Input 1:

8 11 15 2 5 
5

Sample Output 1:

2

Sample Input 2:

8 11 15 2 5 
8

Sample Output 2:

0

int levelSearch(Node* root, int key)
{
//your code here
}

Answer 1

#include <bits/stdc++.h>
using namespace std;
class Node {
public:
int name;
Node* left = NULL;
Node* right = NULL;
};
  
Node* insert( Node* node, int key)
{
if (node == NULL)
{
Node*temp=new Node();
temp->name=key;
return temp;
}
  
if (key < node->name)
node->left = insert(node->left, key);
else if (key > node->name)
node->right = insert(node->right, key);
  
return node;
}

int levelSearch(Node* root, int key)
{
//your code here
int level=0;//here we are declaring initial level as 0
if (root == NULL) return 0;
  
queue<Node *> q; //declaring queue q;
  
q.push(root); //pushing root into q
  
while (q.empty() == false)
{
  
int Count = q.size(); //finding present size of queue at this moment whole level will be in queue
level++;
while (Count > 0)
{
Node *node = q.front();
if(node->name==key) return level; //key found so returning level
q.pop();
if (node->left != NULL)
q.push(node->left); // pushing left node
if (node->right != NULL)
q.push(node->right); // pushing right node
Count--;
}
cout << endl;
}

}
int main() {

Node *root=NULL;
  
int x;
char temp;
do{
scanf("%d%c", &x, &temp);
//cout<<x<<" ";
root=insert(root,x);
} while(temp!= ' ');

int numberToFind;
cin>>numberToFind;

cout<<levelSearch(root,numberToFind);
   return 0;
}Please upvote if you are satisfied or if you have any doubts please post in comment section