Print view of Binary tree

Views of a binary tree, such as top view, bottom view, left view, and right view, refer to the set of nodes visible when the tree is looked at from specific directions. Each view provides a different perspective on the tree.

Table of Contents

Print left view of binary tree

void printLeftView(Node* root) 
{ 
    if (!root) 
        return; 
 
    queue<Node*> q; 
    q.push(root); 
 
    while (!q.empty()) 
    {     
        // number of nodes at current level 
        int n = q.size(); 
         
        // Traverse all nodes of current level 
        for(int i = 1; i <= n; i++) 
        { 
            Node* temp = q.front(); 
            q.pop(); 
                 
            // Print the left most element 
            // at the level 
            if (i == 1) 
                cout<<temp->data<<" "; 
             
            // Add left node to queue 
            if (temp->left != NULL) 
                q.push(temp->left); 
 
            // Add right node to queue 
            if (temp->right != NULL) 
                q.push(temp->right); 
        } 
    } 
}

Print Right View of Binary Tree

void printRightView(Node* root)
{
    if (root == NULL)
        return;
 
    queue<Node*> q;
    q.push(root);
 
    while (!q.empty()) {
        // get number of nodes for each level
        int n = q.size();
 
        // traverse all the nodes of the current level
        while (n--) {
 
            Node* x = q.front();
            q.pop();
 
            // print the last node of each level
            if (n == 0) {
                cout << x->data << " ";
            }
            // if left child is not null push it into the
            // queue
            if (x->left)
                q.push(x->left);
            // if right child is not null push it into the
            // queue
            if (x->right)
                q.push(x->right);
        }
    }
}

Print Top View of Binary Tree

void topView(Node* root) {
    if (!root)
        return;

    std::map<int, int> topViewMap;
    std::queue<std::pair<Node*, int>> q;

    q.push({root, 0});

    while (!q.empty()) {
        Node* current = q.front().first;
        int horizontalDistance = q.front().second;
        q.pop();

        if (topViewMap.find(horizontalDistance) == topViewMap.end()) {
            topViewMap[horizontalDistance] = current->data;
        }

        if (current->left) {
            q.push({current->left, horizontalDistance - 1});
        }

        if (current->right) {
            q.push({current->right, horizontalDistance + 1});
        }
    }

    for (const auto& entry : topViewMap) {
        std::cout << entry.second << " ";
    }
    std::cout << std::endl;
}

Print Bottom View of Binary Tree

void bottomView(Node* root) {
    if (!root)
        return;

    std::map<int, int> bottomViewMap;
    std::queue<std::pair<Node*, int>> q;

    q.push({root, 0});

    while (!q.empty()) {
        Node* current = q.front().first;
        int horizontalDistance = q.front().second;
        q.pop();

        bottomViewMap[horizontalDistance] = current->data;

        if (current->left) {
            q.push({current->left, horizontalDistance - 1});
        }

        if (current->right) {
            q.push({current->right, horizontalDistance + 1});
        }
    }

    for (const auto& entry : bottomViewMap) {
        std::cout << entry.second << " ";
    }
    std::cout << std::endl;
}