Recall & Review
beginner
What does Level Order Traversal (BFS) of a tree mean?
It means visiting all nodes level by level from top to bottom and left to right within each level.
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beginner
Which data structure is commonly used to implement Level Order Traversal?
A queue is used to keep track of nodes to visit in the correct order.
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intermediate
In Level Order Traversal, what happens when you dequeue a node?
You visit the node and enqueue its children (left child first, then right child) if they exist.
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intermediate
Why is Level Order Traversal also called Breadth-First Search (BFS)?
Because it explores all nodes at the current depth before moving to nodes at the next depth, spreading out like a wave.
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beginner
What is the time complexity of Level Order Traversal on a tree with n nodes?
O(n), because each node is visited exactly once.
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Which data structure is essential for implementing Level Order Traversal?
✗ Incorrect
A queue helps process nodes in the order they are discovered, which is key for BFS.
In Level Order Traversal, which node is visited first?
✗ Incorrect
Traversal starts at the root and proceeds level by level.
What is the order of visiting children in Level Order Traversal?
✗ Incorrect
Children are enqueued left to right to maintain correct level order.
What is the space complexity of Level Order Traversal in the worst case?
✗ Incorrect
In the worst case, the queue can hold all nodes at the last level, which can be up to n/2 nodes.
Level Order Traversal is best described as:
✗ Incorrect
Level Order Traversal visits nodes breadth-wise, hence BFS.
Explain how Level Order Traversal (BFS) works on a binary tree.
Think about visiting nodes like reading a book line by line.
You got /4 concepts.
Describe the differences between Level Order Traversal and Depth First Traversal.
Compare exploring neighbors first vs exploring deep paths first.
You got /4 concepts.