Tree Traversal Algorithms

Data Structure and Algorithm 355 views Nov 05, 2025 1 min read

Tree Traversal Algorithms

Tree traversal refers to visiting every node in a tree systematically. It is essential for performing operations such as printing, searching, and modifying nodes.

Types of Tree Traversal

1. Depth-First Traversal (DFS)

DFS explores as far as possible along each branch before backtracking.

Inorder (Left, Root, Right): Used in BST to get elements in sorted order.
Preorder (Root, Left, Right): Used to copy or serialize a tree.
Postorder (Left, Right, Root): Used to delete or evaluate expression trees.

// Example: Inorder traversal (C++)
void inorder(Node* root) {
    if (root != NULL) {
        inorder(root->left);
        cout << root->data << " ";
        inorder(root->right);
    }
}

2. Breadth-First Traversal (Level Order)

Visits nodes level by level from top to bottom using a queue.

// Example: Level Order Traversal
void levelOrder(Node* root) {
    if (root == NULL) return;
    queue q;
    q.push(root);
    while (!q.empty()) {
        Node* current = q.front();
        q.pop();
        cout << current->data << " ";
        if (current->left) q.push(current->left);
        if (current->right) q.push(current->right);
    }
}

Applications

Traversal for printing and searching.
Expression evaluation and syntax parsing.
Serialization and deserialization of trees.

Conclusion

Tree traversal algorithms are essential for processing tree data structures. Choosing the right traversal depends on the specific operation and the structure of the tree.

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Binary Search Trees (BST)

Heaps and Priority Queues