Q72.Marks: +2.0UGC NET Paper 2: Computer Science 2nd January 2026 Shift 1
Consider B+ tree in which the maximum number of keys in a node is 5. What is the minimum number of keys in any non-root node?
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2.2✓ Correct
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Solution
The correct answer is 2.
Key Points
A B+ tree is a type of self-balancing tree data structure that maintains sorted data and allows for efficient insertion, deletion, and search operations.
In a B+ tree, nodes have a minimum and maximum number of keys, based on the order of the tree.
For a B+ tree of order 5, the maximum number of keys in a node is 5.
The minimum number of keys in a non-root node is calculated as ⌈m/2⌉, where m is the order of the tree.
For m = 5, ⌈5/2⌉ = 2, hence the minimum number of keys in a non-root node is 2.
Step-by-Step Solution / Explanation
Formula Used:
Minimum number of keys in a non-root node = ⌈m/2⌉
Step-by-step substitution:
The order of the B+ tree is given as m = 5.
Substitute m = 5 into the formula: ⌈m/2⌉ = ⌈5/2⌉.
Perform the division: 5 ÷ 2 = 2.5.
Apply the ceiling function: ⌈2.5⌉ = 2.
Intermediate calculations:
Order of the tree (m): 5.
Division result: 2.5.
Ceiling function applied: ⌈2.5⌉ = 2.
Final computed result:
The minimum number of keys in a non-root node is 2.
Additional Information
Properties of B+ Trees:
All leaf nodes are at the same level, ensuring balanced height.
Internal nodes act as a guide for searching keys but do not store actual data.
Leaf nodes contain pointers to the next leaf node, forming a linked list for sequential access.
Applications of B+ Trees:
Used in databases and file systems for indexing and efficient data retrieval.
Supports range queries and sequential access efficiently.
Ideal for scenarios requiring balanced search trees with high fan-out.
Advantages of B+ Trees:
Efficient searching, insertion, and deletion due to balanced structure.
Allows for fast sequential access to data via linked leaf nodes.
Minimizes disk I/O operations, making them suitable for large datasets.