Amortized Analysis: A Comprehensive Guide for Data Structures and Algorithms

Question 1

In amortized analysis, we consider which type of performance?

Accepted Answer

Average-case performance over a sequence of operations

Answer

Worst-case performance

Answer

Best-case performance

Answer

Expected performance

Question 2

What is the key concept behind the aggregate method in amortized analysis?

Accepted Answer

Analyzing the average cost of a sequence of operations

Answer

Analyzing the worst-case cost of each operation and then summing them

Answer

Finding a lower bound on the cost of any sequence of operations

Answer

Using a probabilistic model to estimate the average cost of an operation

Question 3

Consider an algorithm that performs a sequence of n operations, where the cost of the i-th operation is c_i. The amortized cost of the algorithm is:

Accepted Answer

Sum of c_i for i from 1 to n divided by n

Answer

Sum of c_i for i from 1 to n

Answer

Maximum of c_i for i from 1 to n

Answer

Minimum of c_i for i from 1 to n

Question 4

Which of the following is not a common technique used in amortized analysis?

Accepted Answer

Divide-and-conquer

Answer

Accounting method

Answer

Aggregate method

Answer

Potential method

Question 5

What is the key principle of amortized analysis?

Accepted Answer

Assessing the average performance of an algorithm across multiple operations.

Answer

Assessing the worst-case performance of an algorithm across multiple operations.

Answer

Assessing the best-case performance of an algorithm across multiple operations.

Answer

Assessing the space complexity of an algorithm across multiple operations.

Question 6

Amortized analysis primarily aims to:

Accepted Answer

Estimate the average-case performance of an algorithm over a sequence of operations

Answer

Determine the exact time complexity of an algorithm

Answer

Identify the worst-case scenario for an algorithm

Answer

Predict the best-case performance of an algorithm

Question 7

The **aggregate method** of amortized analysis considers:

Accepted Answer

The total cost of all operations over a sequence

Answer

The cost of a single operation

Answer

The average cost of all operations

Answer

The worst-case cost of any operation

Question 8

A key insight behind the **accounting method** of amortized analysis is that:

Accepted Answer

The total cost of a sequence of operations can be distributed over the operations

Answer

The cost of each operation is independent of previous operations

Answer

The worst-case cost of an operation is the most relevant measure

Answer

The average cost of an operation is always lower than the worst-case cost

Question 9

Consider an algorithm that performs n operations, each with a cost of O(1). Applying the **accounting method**, what is the amortized cost per operation?

Accepted Answer

O(1)

Answer

O(n)

Answer

O(log n)

Answer

O(n^2)

Question 10

Amortized analysis can

Accepted Answer

Provide a more accurate estimate of algorithm performance than worst-case analysis

Answer

Be more complex to implement than worst-case analysis

Answer

Only be applied to algorithms with regular behavior

Answer

Always result in a lower time complexity bound than worst-case analysis

Question 11

What is the central idea of amortized analysis?

Accepted Answer

Reasoning about the average-case performance of an algorithm over a sequence of operations.

Answer

Analyzing the worst-case performance of an algorithm.

Answer

Reducing the time complexity of an algorithm.

Answer

Applying only to algorithms with a constant running time.

Question 12

What is the primary goal of amortized analysis?

Accepted Answer

To determine the average-case time complexity of an algorithm.

Answer

To determine the worst-case time complexity of an algorithm.

Answer

To determine the best-case time complexity of an algorithm.

Answer

To determine the space complexity of an algorithm.

Question 13

What is the amortized time complexity of a stack operation?

Accepted Answer

O(1)

Answer

O(log n)

Answer

O(n)

Answer

O(n^2)

Question 14

What is the potential function used to analyze the amortized complexity of a binary search tree?

Accepted Answer

The sum of the depths of all nodes in the tree

Answer

The number of nodes in the tree

Answer

The height of the tree

Answer

The number of leaves in the tree

Question 15

What is the amortized cost of a sequence of operations that includes k insertions and k deletions from a linked list?

Accepted Answer

O(k)

Answer

O(k log k)

Answer

O(k^2)

Answer

O(k^3)

Question 16

In amortized analysis, the total cost of a sequence of operations is spread evenly, resulting in an amortized cost per operation of:

Accepted Answer

The average cost of all operations.

Answer

The maximum cost of any single operation.

Answer

The minimum cost of any single operation.

Answer

The worst-case cost of the entire sequence.

Question 17

Which of the following scenarios is well-suited for amortized analysis?

Accepted Answer

An algorithm that performs a large number of operations with varying costs.

Answer

A simple algorithm with predictable behavior.

Answer

An algorithm that has a high worst-case complexity.

Answer

An algorithm that is implemented using a static data structure.

Question 18

The aggregate method in amortized analysis is used to:

Accepted Answer

Sum up the costs of all operations in a sequence.

Answer

Average the costs of all operations in a sequence.

Answer

Identify the operation with the highest cost.

Answer

Estimate the future cost of upcoming operations.

Question 19

Which of the following techniques is used to analyze the amortized time complexity of a binary search tree?

Accepted Answer

Potential method

Answer

Aggregate method

Answer

Accounting method

Answer

Dynamic programming

Question 20

In an amortized analysis, if the potential function is non-negative, it implies that:

Accepted Answer

The actual cost of each operation is always less than or equal to the amortized cost.

Answer

The actual cost of each operation is always greater than or equal to the amortized cost.

Answer

The potential function is increasing over time.

Answer

The amortized analysis is not valid.

Question 21

In a Fibonacci heap, what is the amortized time complexity of decreasing the key of an element?

Accepted Answer

O(log n)

Answer

O(1)

Answer

O(n)

Answer

O(n^2)

Question 22

A disjoint-set data structure uses path compression and union-by-rank heuristics. What is the amortized time complexity of a union operation?

Accepted Answer

O(log n)

Answer

O(1)

Answer

O(n)

Answer

O(n^2)

Question 23

In a skip list data structure, what is the amortized time complexity of a search operation?

Accepted Answer

O(log n)

Answer

O(1)

Answer

O(n)

Answer

O(n^2)

Question 24

What is the key idea behind the accounting method in amortized analysis?

Accepted Answer

Charging the cost of an expensive operation to future operations that benefit from it.

Answer

Assuming that the cost of an operation is equally distributed across all operations in a sequence.

Answer

Ignoring the cost of individual operations and considering only the overall average cost.

Answer

Assuming that the cost of an operation is independent of the number of operations performed.

Question 25

Which of the following is an advantage of using amortized analysis?

Accepted Answer

It can provide more accurate estimates of algorithm performance.

Answer

It is easier to apply than worst-case analysis.

Answer

It always yields better time complexity bounds.

Answer

It eliminates the need for empirical testing.

Question 26

Consider an array of size n that is initially filled with zeros. An operation increments an element in the array by 1. What is the amortized cost of this operation?

Accepted Answer

O(1)

Answer

O(n)

Answer

O(n log n)

Answer

O(n^2)

Question 27

Consider an algorithm that performs n operations. Each operation takes i time units to execute, where i is the operation's index. What is the amortized time complexity of this algorithm?

Accepted Answer

O(n)

Answer

O(1)

Answer

O(n log n)

Answer

O(n^2)

Question 28

Consider a stack implemented using an array. What is the amortized cost of pushing an element onto the stack?

Accepted Answer

O(1)

Answer

O(n)

Answer

O(n log n)

Answer

O(n^2)

Question 29

Which of the following is NOT a key principle in amortized analysis?

Accepted Answer

Deterministic analysis

Answer

Aggregate cost analysis

Answer

Potential method

Answer

Accounting method

Question 30

What is the primary purpose of the accounting method in amortized analysis?

Accepted Answer

To assign costs to individual operations

Answer

To estimate the average cost per operation

Answer

To identify the worst-case scenario

Answer

To verify the correctness of an algorithm

Question 31

What is the amortized cost per operation for a stack that is implemented using a linked list?

Accepted Answer

O(1)

Answer

O(n)

Answer

O(log n)

Answer

O(n^2)

Question 32

Which of the following scenarios is most suitable for applying the potential method in amortized analysis?

Accepted Answer

When operations have varying costs but the average cost is constant

Answer

When the worst-case cost is significantly higher than the average cost

Answer

When the number of operations is unknown

Answer

When the algorithm is inherently sequential

Question 33

What is the primary advantage of amortized analysis over worst-case analysis?

Accepted Answer

It provides a more accurate estimate of the average performance

Answer

It is easier to apply and understand

Answer

It can prove the correctness of an algorithm

Answer

It provides a guaranteed upper bound on the running time

Question 34

What is the difference between the aggregate cost and the amortized cost of an operation?

Accepted Answer

Aggregate cost is the total cost of all operations, while amortized cost is the average cost per operation

Answer

Amortized cost is the total cost of all operations, while aggregate cost is the average cost per operation

Answer

Aggregate cost is the worst-case cost of an operation, while amortized cost is the average cost per operation

Answer

Amortized cost is the worst-case cost of an operation, while aggregate cost is the average cost per operation

Question 35

Which statement best characterizes amortized analysis?

Accepted Answer

Provides an average-case performance guarantee over a sequence of operations.

Answer

Guarantees worst-case performance.

Answer

Only applies to algorithms with predictable behavior.

Answer

Is an optimistic analysis technique.

Question 36

The core principle of amortized analysis involves:

Accepted Answer

Accumulating the costs of operations over time.

Answer

Identifying the most time-consuming operation.

Answer

Establishing a lower bound on algorithmic performance.

Answer

Removing randomness from algorithms.

Question 37

Which of the following scenarios is not suitable for amortized analysis?

Accepted Answer

A single operation on a singly linked list.

Answer

A sequence of random memory accesses.

Answer

A series of insertions and deletions in a hash table.

Answer

A sequence of rotations in a red-black tree.

Question 38

What is the role of the accounting method in amortized analysis?

Accepted Answer

Distributing the cost of expensive operations over multiple operations.

Answer

Identifying operations that contribute significantly to the overall cost.

Answer

Providing a worst-case performance guarantee for the algorithm.

Answer

Eliminating the need for actual cost calculations.

Question 39

When using amortized analysis, what potential drawback should be considered?

Accepted Answer

It can potentially overestimate the actual runtime of an algorithm

Answer

It cannot be applied to all types of algorithms

Answer

It necessitates advanced knowledge of the underlying data structure

Answer

It is overly complex for practical use

Question 40

In amortized analysis, what is the primary purpose of the potential function?

Accepted Answer

Tracking the cumulative cost of operations over time

Answer

Determining the amortized cost of each operation

Answer

Proving the validity of the algorithm

Answer

Reducing the time complexity of the algorithm

Question 41

What is a fundamental distinction between amortized analysis and average-case analysis?

Accepted Answer

Amortized analysis considers costs over a series of operations, while average-case analysis focuses on costs for specific inputs

Answer

Amortized analysis is inherently more accurate than average-case analysis

Answer

Amortized analysis is simpler to apply than average-case analysis

Answer

Amortized analysis is only applicable to algorithms with irregular behavior

Question 42

Which of the following accurately describes the core concept of amortized analysis?

Accepted Answer

Assessing the average performance of an algorithm over a sequence of operations

Answer

Estimating the worst-case running time of an algorithm

Answer

Predicting the exact runtime of an algorithm for a specific input size

Answer

Comparing the efficiency of different algorithms for the same problem

Question 43

Which accounting method is employed to analyze the amortized cost of operations on a queue?

Accepted Answer

Aggregate with accounting

Answer

Aggregate analysis

Answer

Diagonalization

Answer

Backward analysis

Question 44

What is a key advantage of utilizing amortized analysis?

Accepted Answer

It can analyze algorithms that exhibit irregular behavior.

Answer

It provides a more precise estimation of an algorithm's performance.

Answer

It is simpler to apply than aggregate analysis.

Answer

It is always more pessimistic than aggregate analysis.