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Practice Mid-Semester Exam 2
STUDENT NAME
Search students by name or email… ” Q1 Instructions
0 Points
You must acknowledge the following integrity pledge before proceeding. Check the boxes and enter your personal details.
I am committed to being a person of integrity.
I pledge, as a member of the Australian National University community, to abide by and uphold the standards of academic integrity outlined in the ANU statement on honesty and plagiarism, and I am aware of the relevant legislation, and understand the consequences of me breaching those rules.
I will not actively communicate in any way with anyone else during this exam. This includes asking questions in any online forum.
Read and check off the following instructions:
1. You will need to be able to upload code files to this browser from your Haskell workspace. You must also make sure all code you upload compiles without errors.
Make sure this browser window is open on the machine where you plan to work.
If you are working on the ANU Linux VDI this browser window should be open in Linux, not on your personal machine.
If this browser window is not open where you plan to work close this window now and log back into the exam in a browser on your work machine.
2. This examination is timed.
Note the remaining time at the top right of this screen. Set an alarm for yourself if you need one.
3. Permitted materials. This is an open book exam. You might in particular find the course website, the Prelude documentation, and the Data.List documentation useful.
You may use any documentation you wish but all work must be your own.
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Q2 Programming 2 Points
Von Neumann architecture allows
# Storing program code and data in separate memory types
# Storing program code and data in the same memory
# Storing program code in the primary memory but data in the secondary
# Storing data in the primary memory and program code in the secondary
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Q3 Problem classes 2 Points
Given a matrix
A=[a b] cd
the inverse of the matrix exists, iff ad − bc is not zero. Classify the problem of finding the existence of an inverse of A into one of the four classes of problems:
# Functional problems # Decision problems
# Search problems
# Optimization problems
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Q4 Sets 2 Points
If B = {F, T} enumerate all elements of a set produced by B + B+B
# {F,F,F},{F,F,T},{F,T,F},{F,T,T},{T,F,F},{T,F,T},{T,T # {1,F,F},{2,F,T},{3,T,F},{4,T,T},{5,F,F},{6,F,T},{7,T,F # {1,F},{2,F},{3,F},{1,T},{2,T},{3,T}
# {1,F,F},{1,F,T},{1,T,F},{1,T,T},{2,F,F},{2,F,T},{2,T,F
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Q5 Basic types 2 Points
What is the type of the following value ([False, True], [‘0’, ‘1’])
# ([Bool], String) # (Bool, Char)
# (Bool, [Char]) # ([Bool], Char)
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Q6 Function currying 2 Points
The function mod’ is defined as mod’ :: Int -> Int -> Int
mod’ x y = x `mod` y
Which of the following function calls is incorrect? # result = (mod’ 10)
# result = mod’ 10 5
# result = mod’ (10, 5)
# result = (mod’ 10)(5) Save Answer
Q7 Control structures 2 Points
A function safetail :: [a] -> [a] return a tail of a list and maps the empty list to itself.
Select all implementation that fits this function definition.
safetail xs = if null xs then [] else tail xs
safetail xs | null xs = [] | otherwise = tail xs
safetail xs = if null xs then tail xs else []
safetail [] = []; safetail (_:xs) = xs
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Q8 List comprehensions 2 Points
The scalar product of two lists of integers xs and ys of length n is given by the sum of products of corresponding integers
n−1
∑ xsi ∗ ysi
i=0
which of the following functions with type signature
scalarProduct :: [Double] -> [Double] -> Double implements the scalar product:
A.
scalarProduct l1 l2 = sum [x * y | (x, y) <- zip l1 l2] B.
scalarProduct [] _ = 0
scalarProduct _ [] = 0
scalarProduct (x:xs) (y:ys) = x*y + scalarProduct xs ys
C.
scalarProduct l1 l2 = sum [x * y | x <- l1, y <- l2] D.
scalarProduct xs ys = if null xs || null ys
(head xs) * (head ys) + scalarProduct (tail xs) (tail ys)
A B C D
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Q9
2 Points
Upload a Haskell script that completes the following template (instructions included) for the function sumdown .
Cut and paste this template into a working file Sumdown.hs for you to edit and test using ghci before uploading:
module Sumdown where
,
then
0
else
-- | Returns the sum of the non-negative integers
-- from a given value down to zero.
--
-- No type signature for sumDown has been provided;
-- you must work this out for yourself.
--
-- Examples:
--
-- >>> sumdown 3
— 6
sumdown = undefined // TODO $ Please select file(s) Select file(s)
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Q10
2 Points
Upload a Haskell script that completes the following template (instructions included) for the function selectElem .
Cut and paste this template into a working file SelectElem.hs for you to edit and test using ghci before uploading:
module Selectelem where
— | Return a list of elements of the input argument whose length
— equal to the number of occurrences of the input argument in th
is e
— input list.
—
— No type signature for selectElem has been provided;
— you must work this out for yourself.
—
— Examples:
—
— >>> selectElem 3 [5,4,3,3,4,5,6]
— [3,3]
— >>> selectElem ‘l’ “Hello world!”
— “lll”
selectElem = undefined // TODO $ Please select file(s) Select file(s)
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