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Complexity Theory

GATE CSE & IT · 99 questions across 36 years (1987-2026) · 90% recurrence rate

Recurrence sparkline

19872026
198720072026

Difficulty mix

easy 53%
med 46%
hard 1%

Question types

MCQ74
NAT11
MSQ5
OTHER5
STMT2

All 99 questions on Complexity Theory

2026 PYQ

Consider the recursive functions represented by the following code segment: int bar(int n){ if (n == 1) return 0; else return 1 + bar(n/2); } int foo(int n){ if (n == 1) return 1; else return 1 + foo(bar(n)); } The small...

Med
2026 PYQ

Consider an array $A$ of integers of size $n$. The indices of $A$ run from 1 to $n$. An algorithm is to be designed to check whether $A$ satisfies the condition given below. $\forall i, j \in\{1, \ldots, n-1\}$ such that...

Easy
2026 PYQ

Which of the following can be recurrence relation(s) corresponding to an algorithm with time complexity $\Theta(n)$ ?

Easy
2026 PYQ

Consider the following functions, where $n$ is a positive integer. $$ n^{1 / 3}, \log (n), \log (n!), 2^{\log (n)} $$ Which one of the following options lists the functions in increasing order of asymptotic growth rate?...

Easy
2026 PYQ

Consider the following recurrence relations: For all $n>1$, $$ \begin{aligned} & T_1(n)=4 T_1\left(\frac{n}{2}\right)+T_2(n) \\ & T_2(n)=5 T_2\left(\frac{n}{4}\right)+\theta\left(\log _2 n\right) \end{aligned} $$ Assume...

Med
2025 PYQ

Consider the following recurrence relation : $$T(n)=2 T(n-1)+n 2^n \text { for } n>0, T(0)=1$$ Which ONE of the following options is CORRECT?

Med
2025 PYQ

Consider the following C program : #include <stdio.h> int g(int n) { return (n+10); } int f(int n) { return g(n*2); } int main() { int sum, n; sum=0; for (n=1; n The output of the given C program is ________. (Answer in...

Easy
2024 PYQ

Given an integer array of size $N$, we want to check if the array is sorted (in either ascending or descending order). An algorithm solves this problem by making a single pass through the array and comparing each element...

Easy
2024 PYQ

Consider the following C program: #include &ltstdio.h> int main() { int a = 6; int b = 0; while(a Which one of the following statements is CORRECT?

Easy
2024 PYQ

Consider the following C function definition. int f(int x, int y) { for (int i=0; i<y; i++) { x=x+x+y; } return x; } Which of the following statements is/are TRUE about the above function?

Med
2024 PYQ

Consider the following recurrence relation: $$T(n) = \begin{cases} \sqrt{n} T(\sqrt{n}) + n & \text{for } n \ge 1, \\ 1 & \text{for } n = 1. \end{cases}$$ Which one of the following options is CORRECT?

Med
2023 PYQ

Let $$f$$ and $$g$$ be functions of natural numbers given by $$f(n)=n$$ and $$g(n)=n^2$$. Which of the following statements is/are TRUE?

Easy
2023 PYQ

Consider functions Function_1 and Function_2 expressed in pseudocode as follows: Function 1 while n > 1 do for i = 1 to n do x = x + 1; end for n = n/2; end while Function 2 for i = 1 to 100 ∗ n do x = x + 1; end for L...

Easy
2022 PYQ

Which one of the following statements is TRUE for all positive functions f(n) ?

Med
2022 PYQ

Consider the following recurrence : f(1) = 1; f(2n) = 2f(n) $$-$$ 1, for n $$\ge$$ 1; f(2n + 1) = 2f(n) + 1, for n $$\ge$$ 1; Then, which of the following statements is/are TRUE?

Med
2021 PYQ

Consider the following ANSI C program #include <stdio.h> int foo(int x, int y, int q) { if ((x <= 0 && (y <= 0)) return q; if (x <= 0) return foo(x, y - q, q); if (y <= 0) return foo(x - q, y, q); return foo (x, y - q, q...

Med
2021 PYQ

Consider the following three functions. f 1 = 10 n , f 2 = n logn , f 3 = n √n Which one of the following options arranges the functions in the increasing order of asymptotic growth rate?

Med
2021 PYQ

For constants a ≥ 1 and b > 1, consider the following recurrence defined on the non-negative integers : $$T\left( n \right) = a.T\left( {\frac{n}{b}} \right) + f\left( n \right)$$ Which one of the following options is co...

Easy
2021 PYQ

Consider the following ANSI C program. #include <stdio.h> int main( ) { int i, j, count; count = 0; i = 0; for (j = -3; j = 0) && (i++)) count = count + j; } count = count + i; printf("%d", count); return 0; } Which one...

Med
2021 PYQ

Consider the following recurrence relation. $$T(n) = \left\{ {\begin{array}{*{20}{c}} {T(n/2) + T(2n/5) + 7n \ \ \ if\ n > 0}\\ {1\ \ \ \ \ \ \ if\ n = 0} \end{array}} \right.$$ Which one of the following option is corre...

Med
2020 PYQ

For parameters a and b, both of which are $$\omega \left( 1 \right)$$, T(n) = $$T\left( {{n^{1/a}}} \right) + 1$$, and T(b) = 1. Then T(n) is

Med
2019 PYQ

Consider the following C function. void convert(int n){ if(n < 0) printf("%d",n); else { convert(n/2); printf("%d",n%2); } } Which one of the following will happen when the function convert is called with any positive in...

Easy
2019 PYQ

There are n unsorted arrays : A 1 , A 2 , …, A n . Assume that n is odd. Each of A 1 , A 2 , …, A n contains n distinct elements. There are no common elements between any two arrays. The worst-case time complexity of com...

Med
2019 PYQ

Consider the following C program : #include <stdio.h> int main(){ float sum = 0.0, j = 1.0, i = 2.0; while (i/j > 0.0625){ j = j + j; sum = sum + i/j; printf("%f\n", sum); } return 0; } The number of times the variable s...

Easy
2019 PYQ

Consider the following C program: #include < stdio.h > int jumble (int x, int y) { x = 2 * x + y ; return x ; } int main ( ) { int x=2, y=5 ; y = jumble (y, x) ; x = jumble (y, x) ; printf ("%d \n", x) ; return 0 ; } The...

Easy
2018 PYQ

Consider the following C code. Assume that unsigned long int type length is 64 bits. unsigned long int fun(unsigned long int n){ unsigned long int i, j = 0, sum = 0; for (i = n; i > 1; i = i/2) j++; for ( ; j > 1; j = j/...

Easy
2018 PYQ

Consider the following C program: #include < stdio.h > int counter = 0; int calc (int a, int b) { int c; counter++; if (b==3) return (a*a*a); else { c = calc(a, b/3); return (c*c*c); } } int main (){ calc(4, 81); printf...

Easy
2017 PYQ

Consider the following functions from positive integers to real numbers : $10, \sqrt{n}, n, \log _2 n, \frac{100}{n}$. The CORRECT arrangement of the above functions in increasing order of asymptotic complexity is :

Easy
2015 PYQ

Consider the following C program segment. while(first <= last) { if (array[middle] < search) first = middle + 1; else if (array[middle] == search) found = TRUE; else last = middle - 1; middle = (first + last)/2; } if (fi...

Easy
2015 PYQ

Which one of the following assertions concerning code inspection and code walk-through is true?

Easy
2015 PYQ

Consider the following C function. int fun ( int n ) { int x = 1, k ; if ( n == 1) return x ; for( k = 1 ; k < n ; ++ k ) x = x + fun( k ) * fun( n - k ) ; return x ; } The return value of fun (5) is ________.

Med
2015 PYQ

Consider the following pseudo code, where x and y are positive integers. begin q := 0 r := x while r ≥ y do begin r := r - y q := q + 1 end end The post condition that needs to be satisfied after the program terminates i...

Easy
2015 PYQ

Consider a software project with the following information domain characteristics for calculation of function point metric. Number of external inputs $$\left( {\rm I} \right) = 30$$ Number of external outputs $$\left( O...

Med
2015 PYQ

Consider the equality $$\sum\limits_{i = 0}^n {{i^3}} = X$$ and the following choices for $$X$$ $$\eqalign{ & \,\,\,\,\,\,\,{\rm I}.\,\,\,\,\,\,\Theta \left( {{n^4}} \right) \cr & \,\,\,\,\,{\rm I}{\rm I}.\,\,\,\,\,\,\Th...

Easy
2015 PYQ

Consider two decision problems $${Q_1},{Q_2}$$ such that $${Q_1}$$ reduces in polynomial time to $$3$$-$$SAT$$ and $$3$$-$$SAT$$ reduces in polynomial time to $${Q_2}.$$ Then which one of the following is consistent with...

Easy
2015 PYQ

An unordered list contains $$n$$ distinct elements. The number of comparisons to find an element in this list that is neither maximum nor minimum is

Easy
2015 PYQ

Let $$f\left( n \right) = n$$ and $$g\left( n \right) = {n^{\left( {1 + \sin \,\,n} \right)}},$$ where $$n$$ is a positive integer. Which of the following statements is/are correct? $$\eqalign{ & \,\,\,\,\,\,\,{\rm I}.\,...

Med
2015 PYQ

Consider the following C function. int fun1 (int n) { int i, j, k, p, q = 0; for (i = 1; i < n; ++i) { p = 0; for (j = n; j > 1; j = j/2) ++p; for (k = 1; k < p; k = k * 2) ++q; } return q; } Which one of the following m...

Med
2014 PYQ

Which one of the following correctly determines the solution of the recurrence relation with T(1) = 1? T(1) = 2T (n/2) + log n

Easy
2014 PYQ

Consider the following function double f (double x) { if ( abs (x * x – 3) < 0. 01) return x; else return f (x / 2 + 1.5/x); } Give a value q (to 2 decimals) such that f(q) will return q:______.

Med
2014 PYQ

Suppose a polynomial time algorithm is discovered that correctly computes the largest clique in a given graph. In this scenario, which one of the following represents the correct Venn diagram of the complexity classes P,...

Easy📊
2014 PYQ

Consider the decision problem 2CNFSAT defined as follows: { $$\Phi $$ | $$\Phi $$ is a satisfiable propositional formula in CNF with at most two literal per clause} For example, $$\Phi = \left( {{x_1} \vee {x_2}} \right)...

Med
2014 PYQ

Consider the following pseudo code. What is the total number of multiplications to be performed? D = 2 for i = 1 to n do for j = i to n do for k = j + 1 to n do D = D * 3

Med
2014 PYQ

The minimum number of arithmetic operations required to evaluate the polynomial P(X) = X 5 + 4X 3 + 6X + 5 for a given value of X using only one temporary variable is _____.

Med
2013 PYQ

Consider the following function: int unknown(int n) { int i, j, k = 0; for (i = n/2; i <= n; i++) for (j = 2; j <= n; j = j * 2) k = k + n/2; return k; } The return value of the function is

Med
2013 PYQ

Which of the following statements are TRUE? 1. The problem of determining whether there exists a cycle in an undirected graph is in P. 2. The problem of determining whether there exists a cycle in an undirected graph is...

Easy
2013 PYQ

Consider the following operation along with Enqueue and Dequeue operations on queues, where k is a global parameter. MultiDequeue(Q){ m = k while (Q is not empty and m > 0) { Dequeue(Q) m = m - 1 } } What is the worst ca...

Med
2012 PYQ

Let W(n) and A(n) denote respectively, the worst case and average case running time of an algorithm executed on an input of size n. Which of the following is ALWAYS TRUE?

Easy
2012 PYQ

What will be the output of the following C program segment? Char inchar = 'A'; Switch ( inchar ) { case 'A' : printf ("Choice A\ n") ; case 'B' : case 'C' : printf (“Choice B”) ; case 'D' : case 'E' : default : printf (...

Easy
2011 PYQ

Which of the given options provides the increasing order of asymptotic Complexity of functions f 1 , f 2 , f 3 and f 4 ? f 1 = 2 n f 2 = n 3/2 f 3 (n) = $$n\,\log _2^n$$ f 4 (n) = n log 2 n

Easy
2011 PYQ

A company need to develop digital signal processing software for one of its newest inventions. The software is expected to have $$4000$$ lines of code. The company needs to determine the effort in person months needed to...

Med
2011 PYQ

Consider the following recursive C function that takes two arguments: unsigned int foo (unsigned int n, unsigned int r) { if (n > 0) return((n % r) + foo(n/r, r)); else return 0; } What is the return value of the functio...

Easy
2010 PYQ

Two alternate packages A and B are available for processing a database having 10 k records. Package A requires 0.0001n 2 time units and package B requires $$10n.\log _{10}^n$$ time units to process n records. What is the...

Med
2010 PYQ

The following program is to be tested for statement coverage: begin if $$\left( {a = \,\, = b} \right)\,\,\left\{ {S1;\,\,exit;} \right\}$$ else if $$\left( {c = \,\, = d} \right)\,\,\left\{ {S2;} \right\}$$ else $$\left...

Easy
2009 PYQ

The running time of an algorithm is represented by the following recurrence relation: $$T(n) = \begin{cases} n & n \leq 3 \\ T(\frac{n}{3})+cn & \text{ otherwise } \end{cases}$$ Which one of the following represents the...

Easy
2009 PYQ

Consider the following statements about the cyclomatic complexity of the control flow graph of a program module. Which of these are TRUE? $${\rm I}.\,\,\,\,\,\,$$ The cyclomatic complexity of a module is equal to the max...

Med
2008 PYQ

Consider the following functions: F(n) = 2 n G(n) = n! H(n) = n logn Which of the following statements about the asymptotic behaviour of f(n), g(n), and h(n) is true?

Med
2008 PYQ

Consider the following C functions: int f1(int n){ if(n == 0 || n == 1){ return n; } return (2 * f1(n - 1) + 3 * f1(n - 2)); } int f2(int n){ int i; int X[N], Y[N], Z[N]; X[0] = Y[0] = Z[0] = 0; X[1] = 1; Y[1] = 2; Z[1]...

Easy
2008 PYQ

The subset-sum problem is defined as follows: Given a set S of n positive integers and a positive integer W, determine whether there is a subset of S Whose elements sum to W. An algorithm Q solves this problem in O(nW) t...

Med
2008 PYQ

When $$n = {2^{2k}}$$ for some $$k \ge 0$$, the recurrence relation $$$T\left( n \right) = \sqrt 2 T\left( {n/2} \right) + \sqrt n ,\,\,T\left( 1 \right) = 1$$$ evaluates to

Med
2007 PYQ

What is the time complexity of the following recursive function? int DoSomething(int n){ if(n <= 2) return 1; else return (floor(sqrt(n)) + n); }

Med
2007 PYQ

Consider the following segment of C-code: int j, n; j=1; while(j <= n) j = j * 2; The number of comparisons made in the execution of the loop for any n > 0 is:

Easy
2006 PYQ

Let SHAM 3 be the problem of finding a Hamiltonian cycle in a graph G = (V, E) with |V| divisible by 3 and DHAM 3 be the problem of determining if a Hamiltonian cycle exists in such graphs. Which one of the following is...

Med
2006 PYQ

Consider the polynomial $$P\left( x \right) = {a_0} + {a_1}x + {a_2}{x^2} + {a_3}{x^3},$$ where $${a_i} \ne 0,\forall i$$. The minimum number of multiplications needed to evaluate $$p$$ on an input $$x$$ is

Easy
2006 PYQ

Consider the following C-program fragment in which i, j and n are integer variables. for (i = n, j = 0; i > 0; i /= 2, j += i); let val (j) denote the value stored in the variable j after termination of the for loop. Whi...

Med
2006 PYQ

Consider the following recurrence: $$T\left( n \right){\rm{ }} = {\rm{ 2T(}}\left\lceil {\sqrt n } \right\rceil {\rm{) + }}\,{\rm{1 T(1) = 1}}$$ Which one of the following is true?

Med
2005 PYQ

Consider the following C - function: double foo(int n){ int i; double sum; if(n == 0) return 1.0; sum = 0.0; for (i = 0; i < n; i++){ sum += foo(i); } return sum; } The space complexity of the above function is:

Med
2005 PYQ

Suppose T(n) = 2T (n/2) + n, T(0) = T(1) = 1 Which one of the following is FALSE?

Easy
2004 PYQ

Let A[1,...,n] be an array storing a bit (1 or 0) at each location, and f(m) is a function whose time complexity is O(m). Consider the following program fragment written in a C like language: counter = 0; for(i = 1; i <=...

Med
2004 PYQ

The recurrence equation T(1) = 1 T(n) = 2T(n - 1)+n, $$n \ge 2$$ Evaluates to

Med
2004 PYQ

A program takes as input a balanced binary search tree with n leaf nodes and computes the value of a function g(x) for each node x. If the cost of computing g(x) is min{ no. of leaf-nodes in left-subtree of x, no. of lea...

Med
2004 PYQ

The time complexity of the following C function is (assume n > 0) int recursive(int n){ if(n == 1){ return (1); } return (recursive(n - 1) + recursive(n - 1)); }

Easy
2004 PYQ

The goal of structured programming is to

Easy
2003 PYQ

The cube root of a natural number n is defined as the largest natural number m such that $${m^3} \le n$$. The complexity of computing the cube root of n (n is represented in binary notation) is

Med
2003 PYQ

Consider the following three claims I. (n + k) m = $$\Theta \,({n^m})$$ where k and m are constants II. 2 n+1 = O(2 n ) III. 2 2n = O(2 2n ) Which of those claims are correct?

Easy
2002 PYQ

The solution to the recurrence equation T(2 k ) = 3 T(2 k-1 ) + 1, T (1) = 1, is:

Med
2002 PYQ

The running time of the following algorithm Procedure A(n) If n<=2 return (1) else return (A([$$\sqrt n $$])); is best described by

Med
2001 PYQ

Consider the following C program: void abc(char *s) { if(s[0]=='\0') return; abc(s+1); abc(s+1); printf("%c",s[0]); } main() { abc("123"); } (a) What will be the output of the program? (b) If abc(s) is called with a null...

Med
2001 PYQ

Let f(n) = n 2 log n and g(n) = n(log n) 10 be two positive functions of n. Which of the following statements is correct?

Easy
2000 PYQ

Consider the following functions $$f(n) = 3{n^{\sqrt n }}$$ $$g(n) = {2^{\sqrt n {{\log }_2}n}}$$ $$h(n) = n!$$ Which of the following is true?

Med
2000 PYQ

Let s be a sorted array of n integers. Let t(n) denote the time taken for the most efficient algorithm to determined if there are two elements with sum less than 1000 in s. which of the following statements is true?

Easy
1999 PYQ

Consider the following C function definition int Trial (int a, int b, int c) { if ((a > = b) && (c < b)) return b; else if (a > = b) return Trial (a,c,b); else return Trial (b,a,c); } The function Trial:

Med
1999 PYQ

If T 1 = O(1), give the correct matching for the following pairs: List - I (M) T n = T n - 1 + n (N) T n = T n/2 + n (O) T n = T n/2 + nlog n (P) T n = T n - 1 + log n List - II (U) T n = O(n) (V) T n = O(nlogn) (W) T n...

Med
1998 PYQ

Give the correct matching for the following pairs: Group - 1 (A) $${\rm O}(\log n)$$ (B) $${\rm O}(n)$$ (C) $${\rm O}(n\log n)$$ (D) $${\rm O}({n^2})$$ Group - 2 (P) Selection (Q) Insertion sort (R) Binary search (S) Mer...

Easy
1998 PYQ

What value would the following function return for the input x = 95? Function fun (x:integer):integer; Begin If x > 100 then fun : x – 10 Else fun : fun(fun (x + 11)) End;

Med
1998 PYQ

What value would the following function return for the input x = 95? function fun (x:integer):integer; Begin If x > 100 then fun : x – 10 Else fun : fun(fun (x + 11)) End;

Med
1997 PYQ

Let T(n) be the function defined by $$T(1) =1, \: T(n) = 2T (\lfloor \frac{n}{2} \rfloor ) + \sqrt{n}$$ Which of the following statements is true?

Easy
1996 PYQ

The recurrence relation T(1) = 2 T(n) = 3T(n/4) + n has the solution, T(n) equals to

Easy
1996 PYQ

Which of the following is false?

Easy
1996 PYQ

The recurrence relation $$\,\,\,\,\,$$ $$T\left( 1 \right) = 2$$ $$T\left( n \right) = 3T\left( {{n \over 4}} \right) + n$$ has the solution $$T(n)$$ equal to

Easy
1994 PYQ

Conside the following two functions: $${g_1}(n) = \left\{ {\matrix{ {{n^3}\,for\,0 \le n < 10,000} \cr {{n^2}\,for\,n \ge 10,000} \cr } } \right.$$ $${g_2}(n) = \left\{ {\matrix{ {n\,for\,0 \le n \le 100} \cr {{n^3}\,for...

Easy
1994 PYQ

An unrestricted use of the "goto" statement is harmful because

Easy
1993 PYQ

What does the following code do? var a, b : integer; begin a:=a+b; b:=a-b; a:=a-b; end;

Easy
1993 PYQ

$$\sum\limits_{1 \le k \le n} {O(n)} $$ where O(n) stands for order n is:

Easy
1990 PYQ

Express T(n) in terms of the harmonic number H n = $$\sum\limits_{t = 1}^n {1/i,n \ge 1} $$ where T(n) satisfies the recurrence relation, T(n) = $${{n + 1} \over 2}$$ T(n-1) + 1, for $$n \ge 2$$ and T(1) = 1 What is the...

Hard
1989 PYQ

An unrestricted use of the "goto" statement is harmful because of which of the following reason(s):

Easy
1988 PYQ

Solve the recurrence equations: $$\,\,\,\,\,\,\,\,\,\,T\left( n \right) = \left( {{n \over 2}} \right) + 1$$ $$\,\,\,\,\,\,\,\,\,\,\,T\left( 1 \right) = 1$$

Easy
1987 PYQ

Find a solution to the following recurrence equation T(n) = T(n - 1)+ n T(1) = 1

Easy
1987 PYQ

Solve the recurrence equations T (n) = T (n - 1) + n T (1) = 1

Easy