WGU C949 DATA STRUCTURES AND ALGORITHMS OA EXAM– QUESTIONS AND ANSWERS | VERIFIED AND WELL
DETAILED ANSWERS | PLUS RATIONALES | DOWNLOAD AND PASS | LATEST EXAM UPDATE 2026/2027
Core Domains
Data Types and Abstract Data Types
Data Structures (Arrays, Linked Lists, Stacks, Queues, Hash Tables, Trees, Heaps, Graphs)
Algorithm Analysis and Big-O Complexity
Searching and Sorting Algorithms
Recursion and Iteration
Problem-Solving Strategies and Algorithm Design
Introduction
The WGU C949 Objective Assessment evaluates a student's mastery of fundamental data structures and algorithmic
principles. This exam assesses the ability to analyze runtime complexity, select appropriate data structures for specific
scenarios, and interpret pseudocode across various algorithmic paradigms. The questions are designed to test both
conceptual understanding and applied professional knowledge, emphasizing real-world application and critical
decision-making. Candidates must demonstrate proficiency in evaluating trade-offs between different implementations
,and ensuring efficient, scalable solutions. The exam employs multiple-choice and scenario-based questions to measure
readiness for advanced software development tasks.
Section One: Questions 1–50
Question 1
A software engineer needs to store a collection of unique elements and check for the existence of an item in near-
constant average time. Which data structure is most appropriate?
A. Linked List
B. Array
C. Hash Table
D. Binary Search Tree
🟢 Correct Answer: C. Hash Table
🔴 Explanation: A hash table provides O(1) average time complexity for lookups, insertions, and deletions when
using a good hash function, making it ideal for existence checks of unique elements. Arrays and linked lists require
O(n) linear search, while a BST offers O(log n) average time.
Question 2
,Which of the following is a key distinction between a primitive data type and an Abstract Data Type (ADT)?
A. Primitive types are user-defined, while ADTs are language-defined.
B. An ADT encapsulates both data and the operations on that data, exposing behavior through an interface, while a
primitive type exposes only the value itself.
C. ADTs use less memory than primitive types because they avoid built-in language overhead.
D. Primitive types can only be used in object-oriented languages, while ADTs work in any paradigm.
🟢 Correct Answer: B. An ADT encapsulates both data and the operations on that data, exposing behavior through
an interface, while a primitive type exposes only the value itself.
🔴 Explanation: An ADT bundles data with the operations that act on that data, exposing behavior while hiding
internal representation. Primitive types are language-defined built-in types that expose only the raw value.
Question 3
What is the time complexity of inserting an element at the beginning of a singly linked list if you only have a
reference to the head node?
A. O(1)
B. O(log n)
C. O(n)
D. O(n²)
, 🟢 Correct Answer: A. O(1)
🔴 Explanation: Inserting at the head of a singly linked list involves creating a new node, setting its next pointer to
the current head, and updating the head reference. This is a constant-time operation regardless of list size.
Question 4
Given the following pseudocode, what is the worst-case time complexity?
for i = 1 to n:
for j = 1 to i:
print(i, j)
A. O(n)
B. O(n log n)
C. O(n²)
D. O(2^n)
🟢 Correct Answer: C. O(n²)
🔴 Explanation: The inner loop runs an average of n/2 times. The total number of operations is the sum of 1 to n,
which equals n(n+1)/2. In Big-O notation, this simplifies to O(n²).
DETAILED ANSWERS | PLUS RATIONALES | DOWNLOAD AND PASS | LATEST EXAM UPDATE 2026/2027
Core Domains
Data Types and Abstract Data Types
Data Structures (Arrays, Linked Lists, Stacks, Queues, Hash Tables, Trees, Heaps, Graphs)
Algorithm Analysis and Big-O Complexity
Searching and Sorting Algorithms
Recursion and Iteration
Problem-Solving Strategies and Algorithm Design
Introduction
The WGU C949 Objective Assessment evaluates a student's mastery of fundamental data structures and algorithmic
principles. This exam assesses the ability to analyze runtime complexity, select appropriate data structures for specific
scenarios, and interpret pseudocode across various algorithmic paradigms. The questions are designed to test both
conceptual understanding and applied professional knowledge, emphasizing real-world application and critical
decision-making. Candidates must demonstrate proficiency in evaluating trade-offs between different implementations
,and ensuring efficient, scalable solutions. The exam employs multiple-choice and scenario-based questions to measure
readiness for advanced software development tasks.
Section One: Questions 1–50
Question 1
A software engineer needs to store a collection of unique elements and check for the existence of an item in near-
constant average time. Which data structure is most appropriate?
A. Linked List
B. Array
C. Hash Table
D. Binary Search Tree
🟢 Correct Answer: C. Hash Table
🔴 Explanation: A hash table provides O(1) average time complexity for lookups, insertions, and deletions when
using a good hash function, making it ideal for existence checks of unique elements. Arrays and linked lists require
O(n) linear search, while a BST offers O(log n) average time.
Question 2
,Which of the following is a key distinction between a primitive data type and an Abstract Data Type (ADT)?
A. Primitive types are user-defined, while ADTs are language-defined.
B. An ADT encapsulates both data and the operations on that data, exposing behavior through an interface, while a
primitive type exposes only the value itself.
C. ADTs use less memory than primitive types because they avoid built-in language overhead.
D. Primitive types can only be used in object-oriented languages, while ADTs work in any paradigm.
🟢 Correct Answer: B. An ADT encapsulates both data and the operations on that data, exposing behavior through
an interface, while a primitive type exposes only the value itself.
🔴 Explanation: An ADT bundles data with the operations that act on that data, exposing behavior while hiding
internal representation. Primitive types are language-defined built-in types that expose only the raw value.
Question 3
What is the time complexity of inserting an element at the beginning of a singly linked list if you only have a
reference to the head node?
A. O(1)
B. O(log n)
C. O(n)
D. O(n²)
, 🟢 Correct Answer: A. O(1)
🔴 Explanation: Inserting at the head of a singly linked list involves creating a new node, setting its next pointer to
the current head, and updating the head reference. This is a constant-time operation regardless of list size.
Question 4
Given the following pseudocode, what is the worst-case time complexity?
for i = 1 to n:
for j = 1 to i:
print(i, j)
A. O(n)
B. O(n log n)
C. O(n²)
D. O(2^n)
🟢 Correct Answer: C. O(n²)
🔴 Explanation: The inner loop runs an average of n/2 times. The total number of operations is the sum of 1 to n,
which equals n(n+1)/2. In Big-O notation, this simplifies to O(n²).
