WGU C949 DATA STRUCTURES AND ALGORITHMS I
OBJECTIVE ASSESSMENT EXAM 300 QUESTIONS AND
CORRECT DETAILED ANSWERS WITH RATIONALES
(VERIFIED ANSWERS) |AGRADE
What is a characteristic of keys in an associative dictionary data type? –
ANSWER- They are unique and immutable.
Which method can be used to take a value out of a dictionary? –
ANSWER- D1[key].remove(value)
Given this data dictionary in Python:
dict = {‘white’:0x0000, ‘black’:0x1111}
Which command/function generates the output [‘white’,’black’]? –
ANSWER- dict.keys()
Items were added sequentially in this stack starting with ‘ham’:
‘sausage’
‘toast’
‘eggs’
‘ham’
What is the correct order of contents after the push operation is
performed with the value ‘bacon’? – ANSWER- ‘bacon’
‘sausage’
‘toast’
‘eggs’
‘ham’
Items were added sequentially in this stack starting with “dog”:
“bird”
“rabbit”
“cat”
“dog”
What is the return value of the pop operation? – ANSWER- “bird”
Which sequence of letters represents preorder traversal of the nodes of
this tree?
A
/ \
B C
/ \
/ \
D E
\ / \
F G H
/
I – ANSWER- A B C D F E G I H
An array soc of size 1009 is used where the index is an integer in
[0,1008] and the hash-function key%1009.
Where will the data associated with the key given by the last 4 social
security digits ‘2023’ be stored? – ANSWER- In soc[5]
A stack s, a queue q, and a max value priority queue p each have a single
3 in them. Next s.push(4), q.push(4), and p.push(4) are executed.
What is the triple (s.pop(), q.pop(), p.pop())? – ANSWER- (4,3,4)
This stack reads left to right with the top to the right:
‘green’
‘yellow’
‘blue’
‘red’
What could be the stack after a push operation? – ANSWER-
[‘red’,’blue’,’yellow’, ‘green’, ‘purple”]
Items were added sequentially onto the stack starting with ‘red’:
‘green’
‘yellow’
‘blue’
‘red’
What is the stack after a pop operation? – ANSWER- ‘yellow’
‘blue’
‘red’
Which command helps to speed up comparisons using dictionary keys
during a dictionary (d) lookup in this pseudocode clip?
h = hash(key)
for pair in d:
if h == pair[0]:
return pair[1] – ANSWER- hash(object)
What does the method any(b) return in Python if b is a dictionary? –
ANSWER- Returns True if any key of the dictionary is true.
Which Java method is used to read bytes from a standard file? –
ANSWER- Java.io.FileInputStream
Which command will retrieve an item from the top of the stack? –
ANSWER- Pop()
Which command will insert object x at position index in a list? –
ANSWER- Add(int index, Object x)
Which command will return true if x is in a list, otherwise return false? –
ANSWER- Contains(Object x)
When should a dictionary be used instead of a list? – ANSWER- When
the program uses key-value pairs as its data
The reference of the head of the doubly linked list is passed to the
reverse() method:
1<–>2<–>3<–>4<–>5<–>6
What is the modified linked list when complete? – ANSWER- 6<–>5<–
4<–>3<–>2<–>1
Which data structure is indexed? – ANSWER- Array
Which data structure may only store homogeneous data elements? –
ANSWER- Arrays
What is a hierarchical data structure? – ANSWER- Tree
What is an attribute of a binary tree? – ANSWER- Each node has at most
two children.
Which data structure uses a last in, first out (LIFO) removal of items? –
ANSWER- Stack
Given:
heapList = [22, 33, 44, 55, 66]
Which index is the right child of item 22? – ANSWER- 44