Explanation:

- A **Counted B-Tree** is a variant of the B-tree where each node additionally stores the count of the number of elements in the subtree.
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- This allows for efficient range queries, such as finding the k-th smallest element or computing the number of elements less than a given value.

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Steps:

• Insertion: Insert elements while maintaining the B-tree structure and update the counts.
• Querying: Use the stored counts to answer range queries efficiently.

Time Complexity:

• Insertion: O(log n)
• Querying: O(log n)

class CountedBTreeNode:
    def __init__(self):
        self.keys = []
        self.children = []
        self.count = 0
 
class CountedBTree:
    def __init__(self):
        self.root = None
    
    def insert(self, key):
        # Insert and update count
        pass
 
# Example usage
counted_btree = CountedBTree()
counted_btree.insert(5)
counted_btree.insert(10)