Discrete Structure – 300 MCQs
Course-Aligned Multiple Choice Questions for Exam Preparation
Logic, Sets, Relations, Counting, Algorithms, Graphs and Trees
A proposition is a statement that:
Which of the following is a proposition?
The truth value of a tautology is:
A contradiction is a statement that is:
The negation of proposition p is written as:
The conjunction p ∧ q is true when:
The disjunction p ∨ q is false when:
The exclusive OR of p and q is true when:
The implication p → q is false when:
The biconditional p ↔ q is true when:
Which connective means 'and'?
Which connective means 'or'?
Which connective means 'if…then'?
Which connective means 'if and only if'?
The negation of p ∨ q is equivalent to:
The negation of p ∧ q is equivalent to:
De Morgan's laws are mainly used to:
A truth table is used to:
Two propositions are logically equivalent if:
The statement p ∨ ¬p is an example of:
The statement p ∧ ¬p is an example of:
A contingency is a proposition that is:
In logic, precedence is usually highest for:
The converse of p → q is:
The contrapositive of p → q is:
The inverse of p → q is:
An argument is valid if:
Which is a standard rule of inference?
From p and p → q, we infer q by:
From ¬q and p → q, we infer ¬p by:
From p ∨ q and ¬p, we infer q by:
From p and q, we can infer:
From p ∧ q, we can infer:
The law p ∧ q ≡ q ∧ p is called:
The law p ∨ (q ∧ r) ≡ (p ∨ q) ∧ (p ∨ r) is:
Predicate logic extends propositional logic by introducing:
The universal quantifier is written as:
The existential quantifier is written as:
The statement ∀x P(x) means:
The statement ∃x P(x) means:
The negation of ∀x P(x) is:
The negation of ∃x P(x) is:
A predicate becomes a proposition when:
In computing, predicate logic is useful for:
Which proof style starts by assuming the negation of the conclusion?
Which proof method shows p → q by proving ¬q → ¬p?
A direct proof of p → q begins by assuming:
Mathematical induction is commonly used to prove statements about:
The first step in induction is called:
The assumption that P(k) is true in induction is called:
The goal in the inductive step is usually to show:
A set is a:
The symbol ∈ means:
The empty set is denoted by:
The cardinality of a set is its:
If every element of A is also in B, then A is:
A proper subset means:
The union A ∪ B contains elements that are:
The intersection A ∩ B contains elements that are:
Two sets are disjoint if:
The complement of A contains elements:
The set difference A – B contains elements:
The power set of A is the set of:
If a set has n elements, its power set has:
Venn diagrams are useful for:
Ordered pairs are important in defining:
A Cartesian product A × B consists of:
A function from A to B assigns:
The set A in f: A → B is called the:
The set B in f: A → B is called the:
The actual outputs of a function form the:
A function is one-to-one if:
A function is onto if:
A bijection is a function that is:
An inverse function exists only if the function is:
The composition (g ∘ f)(x) means:
The identity function on set A maps each element to:
A recursive function is defined using:
In computer science, recursion usually requires:
A sequence is:
An arithmetic sequence has:
A geometric sequence has:
A mapping is another term commonly used for:
If f(a)=f(b) implies a=b, then f is:
If for each y in B there exists x in A with f(x)=y, then f is:
The floor of 3.9 is:
The ceiling of 3.1 is:
A partition of a set divides it into:
Russell's set paradox motivated careful treatment of:
Finite sets are especially important in CS because many structures are:
Characteristic functions represent sets using:
The symmetric difference A △ B contains elements:
The cardinality formula for two sets is |A ∪ B| =
A countably infinite set has:
Which of the following is countably infinite?
A function from a finite set A to itself that is one-to-one must also be:
The image of subset S under function f is:
Preimage of T under f is:
Many database queries rely heavily on:
A relation from A to B is any subset of:
Binary relations are represented naturally by:
A relation on set A is reflexive if:
A relation is symmetric if:
A relation is antisymmetric if:
A relation is transitive if:
An equivalence relation must be:
A partial order must be:
Equivalence relations partition a set into:
The equivalence class of a under relation R is:
Congruence modulo n is an example of:
The divisibility relation on positive integers is a:
A poset stands for:
In a Hasse diagram, edges usually show:
A maximal element in a poset is one that:
A greatest element in a poset is one that:
A minimal element in a poset is one that:
A least element in a poset is one that:
A lattice is a poset in which every pair has:
The least upper bound is also called:
The greatest lower bound is also called:
A total order is a partial order where:
Recurrence relations define terms using:
The Fibonacci sequence satisfies:
To solve a recurrence uniquely, we usually need:
The recurrence an = an-1 + d defines a:
The recurrence an = r an-1 defines a:
A closed form gives:
Strong induction differs from ordinary induction because it assumes:
Well-ordering principle states that every nonempty set of natural numbers has:
Proof by cases is useful when:
Counterexamples are used to show a statement is:
In software verification, invariants are properties that remain:
Loop invariants are often proved using:
The transitive closure of relation R adds pairs needed to make R:
The reflexive closure of relation R adds:
A relation matrix uses rows and columns to indicate:
Warshall's algorithm computes:
An equivalence relation on a database domain can help identify:
If a relation is reflexive and symmetric but not transitive, it is:
In partial orders, incomparable elements are those for which:
A chain in a poset is a subset where:
An antichain in a poset is a subset where:
Recursive definitions are useful in CS for defining:
An algorithm described recursively often has an implementation using:
Mastering proofs helps in discrete structures because it supports:
The sum 1 + 2 + … + n is often proved by:
A recurrence of the form an = c for all n defines a:
The degree of rigor required in discrete math proofs is important for:
The relation 'is ancestor of' on people is typically:
The relation '=' on any set is:
A recursive algorithm must avoid infinite recursion by having:
A prime number is an integer greater than 1 with:
An integer a divides b if:
The greatest common divisor of 12 and 18 is:
The least common multiple of 4 and 6 is:
Euclidean algorithm is used to find:
If gcd(a,b)=1, then a and b are called:
Fundamental theorem of arithmetic states that every integer greater than 1 can be written as:
A number is even if it is divisible by:
A number is odd if it can be written as:
If a divides b and b divides c, then:
Modular arithmetic deals with remainders after division by:
17 mod 5 equals:
Two integers a and b are congruent modulo n if:
The notation a ≡ b (mod n) means:
In cryptography, modular arithmetic is important because:
A sequence defined by an = n^2 is:
The sum of first n terms of an arithmetic sequence depends on:
The sum of a geometric series with ratio r (|r|<1 in infinite case) depends on:
Factorial of n, written n!, equals:
0! is defined as:
The number of ways to arrange n distinct objects is:
A permutation considers:
A combination considers:
The number of r-combinations from n objects is:
The number of r-permutations from n distinct objects is:
The binomial coefficient nCr counts:
Pascal's identity relates binomial coefficients as:
The binomial theorem expands:
The inclusion-exclusion principle is used to:
For two sets, |A ∪ B| equals:
The pigeonhole principle states that if more than n objects are placed into n boxes, then:
A common application of pigeonhole principle is proving:
If 13 people are in a room, at least two were born in the same:
The number of binary strings of length n is:
A probability value always lies between:
If all outcomes are equally likely, probability of event E is:
The probability of the complement of event E is:
If events A and B are mutually exclusive, then P(A ∪ B) =
If events A and B are independent, then:
Conditional probability P(A|B) means:
Bayes' theorem is useful for:
Expected value in probability is:
A random variable in discrete math usually maps outcomes to:
The number of subsets of an n-element set is:
How many 3-letter strings can be formed from 26 letters if repetition is allowed?
How many ways can 5 distinct books be arranged on a shelf?
How many ways can 2 objects be chosen from 5 distinct objects?
The handshake problem with n people where everyone shakes hands once gives:
Parity arguments are based on whether integers are:
An absurd result such as an integer being both even and odd often indicates:
The sum of first n positive odd numbers is:
The number of functions from an n-element set to a k-element set is:
The number of one-to-one functions from an r-element set to an n-element set (r≤n) is:
Combinatorial reasoning is important in CS for analyzing:
Statistics in discrete structures often summarize:
The mean of values is:
Variance measures:
An algorithm is a:
An algorithm should terminate after:
Correctness of an algorithm means it:
Pseudocode is used to:
Linear search works by:
Binary search requires the data to be:
Binary search repeatedly:
Worst-case time complexity of linear search is:
Worst-case time complexity of binary search is:
Sorting arranges data according to:
Bubble sort repeatedly:
Selection sort repeatedly places:
Insertion sort builds:
Merge sort uses the strategy of:
Quick sort partitions the array around a:
Worst-case complexity of bubble sort is:
Worst-case complexity of merge sort is:
Merge sort is stable if:
Binary search is an example of:
The best data structure for breadth-first exploration of states is often a:
Depth-first processes are commonly implemented using:
Algorithm complexity is often expressed using:
O(n^2) grows compared to O(n log n) as n becomes large:
An invariant in sorting is:
A stable sort preserves:
A comparison-based sort cannot do better in worst case than:
Recursive algorithms often use stack memory because of:
An iterative procedure typically uses:
Algorithm analysis helps compare:
Searching a linked list efficiently with binary search is generally:
A graph consists of:
A simple graph has:
In an undirected graph, an edge {u,v} means:
The degree of a vertex in an undirected graph is:
In a directed graph, the number of incoming edges is:
A path is:
A cycle is a path that:
A graph is connected if:
A connected acyclic graph is called a:
The sum of degrees of all vertices in an undirected graph equals:
A planar graph can be drawn:
Euler's formula for a connected planar graph is:
Graph coloring assigns:
The chromatic number of a graph is:
A bipartite graph can be colored with at most:
A complete graph on n vertices is denoted by:
A complete graph Kn has how many edges?
A subgraph contains:
A walk may:
A trail is a walk with no repeated:
A simple path has no repeated:
An Euler circuit uses:
A connected graph has an Euler circuit iff every vertex has:
A Hamiltonian path visits:
A Hamiltonian cycle is a cycle that visits:
Dijkstra's algorithm finds:
Breadth-first search on an unweighted graph finds:
Depth-first search is useful for:
A spanning tree of a connected graph contains:
A minimum spanning tree is defined for:
Kruskal's algorithm builds a minimum spanning tree by:
Prim's algorithm grows a minimum spanning tree from:
An adjacency matrix of a graph is especially convenient for:
An adjacency list is usually memory-efficient for:
Topological sorting applies to:
A tree is a connected graph with:
A rooted tree is a tree with:
In a rooted tree, the parent of a node is:
A leaf in a tree is a vertex with:
The level or depth of a node is its distance from the:
The height of a rooted tree is:
A binary tree is a rooted tree where each node has at most:
A full binary tree is one in which every internal node has:
A complete binary tree fills levels:
Preorder traversal visits:
Inorder traversal of a binary tree visits:
Postorder traversal visits:
Level-order traversal is commonly implemented using a:
Expression trees are useful for representing:
A subtree of a node consists of:
A forest is:
Removing the root from a rooted tree yields:
For any tree with n vertices, the number of edges is:
A tree with one root and branching choices naturally models:
File systems and organization charts are often modeled using:
A spanning tree of a graph helps remove:
Decision trees in computing represent:
The children of a node are:
The siblings of a node are nodes that share the same:
Traversals are important because they define systematic ways to:
A balanced binary search tree generally supports search in:
Depth-first traversal of a tree is naturally expressed using:




