Question 1

Computer programmers decide which data structures to use based on the nature of the data.

Accepted Answer

Computer programmers choose data structures based on the nature of the data and the operations that need to be performed on it, to optimize performance, efficiency, and resource usage.

Question 2

Data exits a queue in the same order in which it entered the queue.

Accepted Answer

This statement describes the fundamental behavior of a queue, which operates on a First In, First Out (FIFO) principle, meaning data exits in the same order it entered.

Question 3

A graph is a common data structure.

Accepted Answer

A graph is a widely used data structure in computer science for representing relationships between pairs of objects.

Question 4

A binary tree is good for storing information that needs to be searched quickly, such as a dictionary or phone directory.

Accepted Answer

Binary trees, especially balanced ones like AVL or Red-Black trees, provide efficient search operations (logarithmic time complexity), making them suitable for quickly accessing sorted data, such as dictionaries or phone directories.

Question 5

A queue would be a good data structure to use for keeping track of documents waiting to be printed on a networked printer.

Accepted Answer

A queue operates on a First In, First Out (FIFO) principle, which is ideal for managing tasks like printing documents in the order they were sent to the printer.

Question 6

A queue is a very good data structure to use for a set of objects that needs to be searched quickly.

Accepted Answer

A queue is designed for operations like enqueue (insertion) and dequeue (removal) following the First-In-First-Out (FIFO) principle, not for quick search operations. For quick searches, data structures like hash tables or binary search trees are more efficient.

Question 7

You should always start searching a binary tree by looking at the root node.

Accepted Answer

The root node is the starting point of a binary tree, and searching or traversing a binary tree typically begins from the root node to reach other nodes.

Question 8

The efficiency of the binary tree comes from the fact that each time you look at a node, you either find the item you want, or move down one level in the tree. This cuts the remaining data to be searched in half.

Accepted Answer

Binary trees, especially balanced binary trees like AVL or Red-Black trees, offer efficient search operations because at each step of searching, you eliminate half of the remaining elements by choosing which subtree to traverse based on the node's value. This binary decision-making process results in a time complexity of O(log n) for search operations, making it highly efficient for data retrieval compared to linear data structures.

Question 9

To find an item in a queue, you need to start at one end of the queue and go through each item, one at a time, until you find the item for which you are searching.

Accepted Answer

Queues are a First-In-First-Out (FIFO) data structure, meaning items are processed in the order they were added. To find an item, you must start from the front and sequentially move through each item until the desired one is found.

Question 10

On average, you will need to look at 500 items to find a single object in a queue with 1,000 items.

Accepted Answer

In a queue with 1,000 items, on average, you would need to look at half of them, which is 500, to find a specific object.

Question 11

In a binary tree with a thousand items, the longest it would take to find any item is 1/10th of a second.

Accepted Answer

The longest it would take to find any item in a binary tree with a thousand items is 10 steps, which would take 1/10th of a second.

Question 12

Alice also has two instructions to manipulate lists - For all in order and For all together.

Accepted Answer

Alice is a programming language that includes instructions for manipulating lists, such as "For all in order" and "For all together," which allow iteration over list elements.

Question 13

For all together will perform an operation on each item in a list one at a time, beginning with the first item in the list and going through the list in order.

Accepted Answer

The phrase "for all together" does not accurately describe how operations are performed on items in a list in programming. Instead, a "for loop" iterates over each item in a list one at a time, in order.

Question 14

For all in order will perform an operation on all of the items in a list at the same time.

Accepted Answer

The phrase "for all in order" typically refers to iterating over items in a sequence one at a time, not performing operations on all items simultaneously.

Question 15

Do in order and Do together operate on a set of objects.

Accepted Answer

"Do in order" and "Do together" are programming constructs used to control the sequence of actions, not operations on a set of objects. "Do in order" ensures actions are performed sequentially, while "Do together" allows for parallel execution.

Question 16

For all in order and For all together operate on a set of instructions.

Accepted Answer

"For all in order" and "For all together" are not standard programming or mathematical terms commonly used to describe operations on a set of instructions.

Question 17

An array is a set of objects.

Accepted Answer

An array is a data structure that contains a collection of elements, typically of the same data type, stored at contiguous memory locations. It is not a set, which is a collection of distinct objects.

Question 18

A list is a set of variables that hold objects.

Accepted Answer

A list is a collection of items in a particular order, not a set of variables. Lists can hold objects, but they are not sets.

Question 19

In mathematics, especially matrix algebra, index values for elements in an array are usually subscripted.

Accepted Answer

In matrix algebra and other areas of mathematics, elements in an array or matrix are typically identified by their position using subscripted index values, such as $a_{ij}$ to denote the element in the $i$th row and $j$th column.

Question 20

An array of the names of four cities might be referred to as city₀, city₁, city₂, and city₃, or as city[0], city[1], city[2], and city[3].

Accepted Answer

In programming, arrays are zero-indexed, meaning the first element is accessed with the index 0. Therefore, an array of four cities can indeed be referred to using indices 0 through 3, as in city[0], city[1], city[2], and city[3]. The notation with subscripts (city₀, city₁, etc.) is a mathematical or conceptual representation, while the square bracket notation (city[0], city[1], etc.) is commonly used in programming languages like JavaScript, Python, and many others to access array elements.

Quiz 8: Lists and Arrays in Alice