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13 - Practice Test

 1. An algorithm is essentially the exact same thing as binary code. The terms are used interchangeably.

  FALSE

  TRUE

 2. What is the name of this searching algorithm?
array people[5] 
people = [“Imogen”, “Fletcher”, “Kirstie”, “Zoe”, “Gavin”]
found = False
x = 0
searchfor = input(“enter a name to search for : “)
while found = False AND x <5
	    if people[x] = searchfor then	        found = True
	        print “found at position” + x
	        x = x + 1
	    endif
Endwhile

  bubble search

  insertion search

  binary search

  linear search

 3. A binary search compares each value in turn starting at the first element.

  TRUE

  FALSE

 4. The programmer wants a variable inside a function to be treated as 'global' and the following code achieves this.
def func1():
 global some_global #use global keyword
 my_global = 20

  FALSE

  TRUE

 5. The following statement will evaluate to ……
(10 >= 1) and (1 < 2)

  TRUE

  FALSE

 6. The following statement will evaluate to …..
>>> (1>2) and (9>=1)

  FALSE

  TRUE

 7. In the following algorithm, the elif has _____ conditional tests.
limbs = 4
if limbs == 4:
 print('no one shall pass')
elif limbs > 0 <4:
 print('tis but a scratch')
else:

  3

  4

  2

  1

 8. What is the output of the following code?
n = 0
for num in range(5):
 n = n + num
print (n)

  10

  20

  5

  15

 9. Which of the following statements is correct, in reference to the following code?
while answer!=”computer”
 answer=input(“What is the
password?”)
endwhile
do
 answer=input(“What is the
password?”)
until answer == “computer”

  The while loop will keep looping while its condition is True.

  The while loop will stop if the condition is True

  The while loop will end if the answer is = "open123"

  None of the above

 10. Merge sort is known as a recursive algorithm. What is a recursive function?

  There is no such thing

  A recursive algorithm is just an algorithm which uses a loop

  None of the above

  A recursive algorithm is an algorithm which calls itself with "smaller (or simpler)" input values, and which obtains the result

 11. Can you spot the place in the code for merge sort where recursion is taking place (a function calling itself)
def mergeSort(alist):

   print("Splitting ",alist)

   if len(alist)>1:
       mid = len(alist)//2
       lefthalf = alist[:mid]
       righthalf = alist[mid:]

       #recursion
       mergeSort(lefthalf)
       mergeSort(righthalf)

       i=0
       j=0
       k=0

       while i < len(lefthalf) and j < len(righthalf):
           if lefthalf[i] < righthalf[j]:
               alist[k]=lefthalf[i]
               i=i+1
           else:
               alist[k]=righthalf[j]
               j=j+1
           k=k+1

       while i < len(lefthalf):
           alist[k]=lefthalf[i]
           i=i+1

  There is no recursion in this program - there's no such thing!

  Line 15 and 16

  Line 11 and 12

  Line 9 and 10

 12. Linear search runs in at worst linear time and makes at most n comparisons, where n is ….

  the length of the list

  the letter 'n'

  the number of the first element

  the number of the second element

 13. Analyse the code below - what is the search criteria here?
#demonstration of linear search

def linearsearch(x,mylist):
  found=False
  
  for i in range(len(mylist)):
    if x==mylist[i]:
      found=True
      break
    else:
      if x not in mylist:
        break

  if found==False:
     print("Not Found")
  else:
    print("Found in position",i)

     

mylist=[1,2,3,4,5]
x=int(input("Enter a number:"))
linearsearch(x,mylist)
  

  found' is the input and is the search criteria

  x' is input by the user and is the search criteria

  int' is the search criteria

  mylist' is the search criteria in the coded example

 14. In a linear search, each element of the list is checked sequentially (one after the other) starting …
If you are able, watch the video and try and code this yourself in order to fully master it.

  at the beginning of the list

  at a random point in the list

  at the end of the list

  in the middle of the list

 15. At each step of the algorithm an element is moved from the ..

  None of the above

  unsorted portion into the sorted portion until the whole list is sorted

  sorted portion into the unsorted portion until the list is unsorted

  unsorted portion into the unsorted portion

 16. Typically, the sorted numbers go to the _____of the unsorted numbers.

  right

  left

  infront

  behind

 17. In the following list what is '23'?
23,42,4,16,8,15

  The end point of our unsorted portion

  None of the above

  The start and end of our unsorted portion

  The start and end of our sorted portion

 18. 42 is the first element in the unsorted portion and we proceed in the algorithm to …..
23,42,4,16,8,15

  None of the above

  compare the 42 to the 23 (23 being the only element in our sorted element)

  compare the 42 to the 15

  compare the 42 to the 4

 19. If 42 is larger than 23, we can…..
23,42,4,16,8,15

  None of the above

  include 42 before the 23 (e.g. 42,23 / etc)

  remove 42 and take it to the end of the list as it is largest (e.g. 23,4,16,8,15,42)

  append 42 to the end of the 'sorted' list. (e.g. 23, 42 / 4,16,8,15

 20. What are the correct intermediate steps of the following data set when it is being sorted with the bubble sort? 15,20,10,18

  15,10,20,18 -- 15,10,18,20 -- 10,15,18,20

  All of the above are valid options

  10, 20,15,18 -- 10,15,20,18 -- 10,15,18,20

  15,18,10,20 -- 10,18,15,20 -- 10,15,18,20 -- 10,15,18,20

 21. It is possible to code a bubble sort with two 'for loops' nested in each other

  FALSE

  TRUE

 22. What is the maximum number of comparisons if there are 5 elements in array x?

  6

  2

  10

  5

 23. What is the max. number of comparisons that can take place when a bubble sort is implemented? Assume there are n elements in the array?

  (1/2)n(n-1)

  (1/2)(n-1)

  None of the above

  (1/4)n(n-1)

 24. In the following code, what is the line for i in range(n) doing?
def bubbleSort(arr):
    n = len(arr)
 
   
    for i in range(n):
 
        # Last i elements are already in place
        for j in range(0, n-i-1):
 
            # traverse the array from 0 to n-i-1
            # Swap if the element found is greater
            # than the next element
            if arr[j] > arr[j+1] :
                arr[j], arr[j+1] = arr[j+1], arr[j]

  None of the above

  It is performing the swap FOR every element that is greater

  It is performing the swap FOR every element that is smaller than the first element

  It is looping/traversing through all the elements in the array (or list)

 25. In the following flow chart, if the numbers 1,2,3,4,5 are entered what is the output?
findthesumof5numbers_flowchart.png

  15

  12

  10

  5

 26. Indicates any type of internal operations like initialization, calculation etc.

  Process

  Decision

  Terminal

  Connector

 27. Used for asking questions that can have either TRUE or FALSE (YES or NO) as an answer.

  Process

  Terminal

  Decision

  Connector

 28. Indicates the starting or ending of the algorithm.

  Terminal

  Connector

  Decision

  Process

 29. The following pseudocode will accept a password string as a parameter passed into the function, returning _____ if the password is a valid length or ______ if it is not valid.
function checkpassword(password)
if password.length >= 8 then
return True
else
return False
endfunction

  True / True

  True / False

  False / True

  False / False

 30. A car dealer uses the following algorithm to determine the price to charge for cars. What is the output if p = 1000 i=2 and a = 12?
01 p = input(“purchase price of car”		02 i = input(“number of improvements made”)
		03 a = input(“age of car in years”)
		04 s = p + (i*100)
		05 if a <= 10 then
		06     s = s + s
		07 endif
		08 print  “sale price is “ + s

  None of the above

  16000

  1200

  10600