Recall & Review
beginner
What is the bottom view of a binary tree?
The bottom view of a binary tree is the set of nodes visible when the tree is seen from the bottom. It shows the last node at each horizontal distance from the root.
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beginner
How do we assign horizontal distances to nodes in a binary tree for bottom view?
We assign 0 to the root. For left child, horizontal distance is parent's distance minus 1. For right child, it is parent's distance plus 1.
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intermediate
Which data structure is commonly used to track nodes and their horizontal distances during bottom view traversal?
A queue is used for level order traversal, and a map (or dictionary) stores the latest node at each horizontal distance.
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intermediate
Why does the bottom view use level order traversal instead of in-order or pre-order?
Level order traversal processes nodes level by level, ensuring the bottom-most node at each horizontal distance overwrites previous nodes in the map.
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beginner
What is the time complexity of computing the bottom view of a binary tree with n nodes?
The time complexity is O(n) because each node is visited once during level order traversal.
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What horizontal distance is assigned to the root node in bottom view calculation?
✗ Incorrect
The root node is always assigned horizontal distance 0.
Which traversal method is best suited for computing the bottom view of a binary tree?
✗ Incorrect
Level order traversal visits nodes level by level, which helps track the bottom-most nodes.
In bottom view, what happens if two nodes share the same horizontal distance and level?
✗ Incorrect
The last node visited at that horizontal distance overwrites the previous one in the map.
What data structure helps store the bottom-most node at each horizontal distance?
✗ Incorrect
A map stores the latest node for each horizontal distance during traversal.
What is the time complexity of the bottom view algorithm for a binary tree with n nodes?
✗ Incorrect
Each node is visited once, so the time complexity is O(n).
Explain how to compute the bottom view of a binary tree step-by-step.
Think about horizontal distances and level order traversal.
You got /5 concepts.
Why is level order traversal important for the bottom view of a binary tree?
Consider how nodes at the same horizontal distance but different levels are handled.
You got /3 concepts.