CS 412: Introduction to Data Mining Homework 2 solution

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2 Question 1 (1 point)
A data cube, C, has d dimensions, and n nonempty cells in the base cuboid. Assume that
there are no concept hierarchies associated with the dimensions.

1. What could be the maximum number of cells (including both base cells and aggregate
cells) in the data cube, C?

2. What could be the minimum number of cells (including both base cells and aggregate
cells) in the data cube, C?

3 Question 2 (1 point)
Assume you are exploring a dataset with five attributes {A, B, C, D, M}, where M is a
continuous attribute, and the remaining attributes are binary. You are looking at a view
V1 that shows the SUM of M, for the two possible values of A.

Now, if you perform two
sequential operations on V1: (i) drill-down by choosing an attribute from {B, C, D} for
de-aggregation, and (ii) slicing by choosing a filter criterion on one of the attributes from
{A, B, C, D}, you would get a new view V2.

Now, consider another user who is looking at the
same original view V1. If s/he performs the same set of operations on V1 (same de-aggregation
attribute and filter criterion), however, in reverse order (first slicing, then drill-down), and
gets a view V3, can V2 and V3 be different? Explain why the two views can (can not) be
different.

4 Question 3 (6 points)
Participate in the programming contest hosted at hackerrank:
https://www.hackerrank.com/contests/hw-2-sp-2018/.

Please pay special attention to the output format. There will be no manual grading for the programming problem. So you need to strictly follow the formatting
rules.