Maximum_Width_Of_Binary_Tree.cpp

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

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

// } Driver Code Ends
/*  Structure of a Binary Tree

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

    Node(int x){
        data = x;
        left = right = NULL;
    }
};
 */

class Solution
{
public:
    // Function to get the maximum width of a binary tree.
    int getMaxWidth(Node *root)
    {
        if (!root)
            return 0;

        int maxWidth = -1;
        queue<Node *> q;
        q.push(root);
        while (!q.empty())
        {
            int size = q.size();
            maxWidth = max(maxWidth, size);
            while (size--)
            {
                Node *node = q.front();
                q.pop();
                if (node->left)
                    q.push(node->left);
                if (node->right)
                    q.push(node->right);
            }
        }
        return maxWidth;
    }
};

//{ Driver Code Starts.

int main()
{
    int t;
    cin >> t;
    getchar();
    while (t--)
    {
        string inp;
        getline(cin, inp);
        Node *root = buildTree(inp);

        Solution ob;
        cout << ob.getMaxWidth(root) << endl;
    }
    return 0;
}

// } Driver Code Ends
// LeetCode Solution

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
/*
class Solution {
public:
    int widthOfBinaryTree(TreeNode* root) {
        if(!root) return 0;
        int ans = INT_MIN;
        queue<pair<TreeNode*, int>> q;
        q.push({root, 0});
        while(!q.empty())
        {
            int size = q.size();
            int mmin = q.front().second;
            int first, last;
            for(int i = 0; i < size; i++)
            {
                long curr_id = q.front().second-mmin;
                TreeNode * node = q.front().first;
                q.pop();
                if(i == 0) first = curr_id;
                if(i == size-1) last = curr_id;
                if(node->left)
                    q.push({node->left, curr_id * 2 + 1});
                if(node->right)
                    q.push({node->right, curr_id * 2 + 2});
            }
            ans = max(ans, last-first+1);
        }
        return ans;
    }
};

*/