LCA of BST.cpp

#include <iostream>
#include <queue>
using namespace std;
// Following is the Binary Tree node structure
class BinaryTreeNode {
    public : 
    T data;
    BinaryTreeNode<T> *left;
    BinaryTreeNode<T> *right;

    BinaryTreeNode(T data) {
        this -> data = data;
        left = NULL;
        right = NULL;
    }
};

int lcaInBST(BinaryTreeNode<int>* root , int val1 , int val2){

  if(root==NULL)
    return -1;
  if(root->data==val1&&root->data==val2)
    return root->data;
 int a,b; 
if(val1>root->data&&val2>root->data)
{  a= lcaInBST( root->right ,val1 ,val2);
   return a;
}
if(val1<root->data&&val2<root->data)
{ b= lcaInBST( root->left ,val1 ,val2);
   return b;
}

}
BinaryTreeNode<int>* takeInput() {
    int rootData;
    //cout << "Enter root data : ";
    cin >> rootData;
    if(rootData == -1) {
        return NULL;
    }
    BinaryTreeNode<int> *root = new BinaryTreeNode<int>(rootData);
    queue<BinaryTreeNode<int>*> q;
    q.push(root);
    while(!q.empty()) {
        BinaryTreeNode<int> *currentNode = q.front();
	q.pop();
        int leftChild, rightChild;
        //cout << "Enter left child of " << currentNode -> data << " : ";
        cin >> leftChild;
        if(leftChild != -1) {
            BinaryTreeNode<int>* leftNode = new BinaryTreeNode<int>(leftChild);
            currentNode -> left =leftNode;
            q.push(leftNode);
        }
        //cout << "Enter right child of " << currentNode -> data << " : ";
        cin >> rightChild;
        if(rightChild != -1) {
            BinaryTreeNode<int>* rightNode = new BinaryTreeNode<int>(rightChild);
            currentNode -> right =rightNode;
            q.push(rightNode);
        }
    }
    return root;
}
int main() {
    BinaryTreeNode<int>* root = takeInput();
    int a, b;
    cin >> a >> b;
    cout << lcaInBST(root, a, b);
    delete root;
}