minimumelementinBST.cpp

#include <bits/stdc++.h>
using namespace std;

struct Node
{
    int data;
    struct Node *left;
    struct Node *right;
};
// Utility function to create a new Tree Node
Node* newNode(int val)
{
    Node* temp = new Node;
    temp->data = val;
    temp->left = NULL;
    temp->right = NULL;
    
    return temp;
}
// 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 = newNode(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 = newNode(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 = newNode(stoi(currVal));
                
            // Push it to the queue
            queue.push(currNode->right);
        }
        i++;
    }
    
    return root;
}

int minValue(Node *root);

int main()
{
    int t;
	scanf("%d ",&t);
    while(t--)
    {
        string s;
		getline(cin,s);
        Node* root = buildTree(s);
        cout <<minValue(root) << endl;
    }
    return 1;
}// } Driver Code Ends


/*int minValue(Node* root)
{
    int min=0;
    //apply dfs or bfs traversal to find trhe minimum elem in bst
    for(int i=0;i<n;i++)
    //store node value in hash stack queue or array
    arr[node+n]={0};
    if(current_node[i]<min)
    min=current_node[i];
    return min;
    
}*/int minValue(Node * root){
     
     while(root->left!=NULL){
       root=root->left;
     }
       return (root->data);
}