Check for BST.cpp

//{ Driver Code Starts
#include <bits/stdc++.h>
using namespace std;
#define MAX_HEIGHT 100000

// Tree Node
struct Node {
    int data;
    Node* left;
    Node* right;

    Node(int val) {
        data = val;
        left = right = NULL;
    }
};


// } Driver Code Ends
class Solution {
  public:
    // Function to check whether a Binary Tree is BST or not.
//     struct newNode{
//     int data;
//     int maxi;
//     int mini;
//     newNode(int val,int maxi,int mini){
//         data = val;
//         this->maxi = maxi;
//         this->mini= mini;
//     }
// };
// class Solution {
//   public:
//     // Function to check whether a Binary Tree is BST or not.
    
//   newNode* solve (Node* root){
//         if (root == NULL) {
           
//             return new newNode(INT_MIN, INT_MIN, INT_MAX);
//         }
//       if(root->left == NULL && root->right==NULL){
//           return new newNode(root->data,root->data,root->data);
//       }
//       newNode* left = solve(root->left);
//       newNode* right = solve(root->right);
       
//       if(left->maxi<root->data && root->data<right->mini){
//           return new newNode(root->data,max(left->maxi,root->data),min(root->data,right->mini));
//       }
       
//       return new newNode(INT_MIN,INT_MAX,INT_MIN);
//   }
//     bool isBST(Node* root) {
//         // Your code hereve
//         newNode* rootNew = solve(root);
        
//         if(rootNew->data ==INT_MIN) return false;
//         return true;
//     }
// };

    
    
    
 
    // Function to check whether a Binary Tree is BST or not.
    void solve(Node* root, vector<int>&ans){
        if(root==NULL) return ;
        solve(root->left,ans);
        ans.push_back(root->data);
        solve(root->right,ans);
    }
    bool isBST(Node* root) {
        // Your code hereve
        vector<int>ans;
        
        solve(root,ans);
        
        for(int i=1;i<ans.size();i++){
            if(ans[i-1]>=ans[i]) return false;
        }
        return true;
    }
};


//{ Driver Code Starts.

// Function to Build Tree
Node* buildTree(string str) {
    // Corner Case
    if (str.length() == 0 || str[0] == 'N')
        return NULL;

    // Creating vector of strings from input
    // string after spliting by space
    vector<string> ip;

    istringstream iss(str);
    for (string str; iss >> str;)
        ip.push_back(str);

    // Create the root of the tree
    Node* root = new Node(stoi(ip[0]));

    // Push the root to the queue
    queue<Node*> queue;
    queue.push(root);

    // Starting from the second element
    int i = 1;
    while (!queue.empty() && i < ip.size()) {

        // Get and remove the front of the queue
        Node* currNode = queue.front();
        queue.pop();

        // Get the current node's value from the string
        string currVal = ip[i];

        // If the left child is not null
        if (currVal != "N") {

            // Create the left child for the current node
            currNode->left = new Node(stoi(currVal));

            // Push it to the queue
            queue.push(currNode->left);
        }

        // For the right child
        i++;
        if (i >= ip.size())
            break;
        currVal = ip[i];

        // If the right child is not null
        if (currVal != "N") {

            // Create the right child for the current node
            currNode->right = new Node(stoi(currVal));

            // Push it to the queue
            queue.push(currNode->right);
        }
        i++;
    }

    return root;
}

void inorder(Node* root, vector<int>& v) {
    if (root == NULL)
        return;

    inorder(root->left, v);
    v.push_back(root->data);
    inorder(root->right, v);
}

int main() {

    int t;
    string tc;
    getline(cin, tc);
    t = stoi(tc);
    while (t--) {
        string s;
        getline(cin, s);
        // if (s[0] == '9') {
        //     cout << "false\n";
        //     return 0;
        // }
        Node* root = buildTree(s);
        Solution ob;
        if (ob.isBST(root))
            cout << "true\n";

        else
            cout << "false\n";
    }
    return 0;
}

// } Driver Code Ends