C++ Interview Questions on Time & Space Complexity

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Question: 1

What is the time complexity of the following C++ code? 

int sum;
int i = 0;
int j = N; 

while (i <= j) { 
   sum = sum + i;
   i++;
}

(A) O(log N)
(B) O(N/2)
(C) O(N)
(D) O(N^2)

Compiler
Level: Beginner Category: time_space_complexity

Question: 2

What is the time complexity of the following C++ code? 

for(int var = 0; var<=N; )
{
    cout<<var<<endl;
    var = var + 2;
}

(A) Compilation error
(B) O(logN)
(C) O(N/2)
(D) O(N)

Compiler
Level: Practionar Category: time_space_complexity

Question: 3

What is the time complexity of the following C++ code? 

int myFunction(int N, int M)
{
    for(int k=5; k<=N; k++)
    {
        cout<<k*2;
    }

    for(int l=5; l<=N; l++)
    {
        cout<<l*3;
    }
    return 0;
}

(A) O(2N)
(B) O(N)
(C) O(N+N)
(D) O(N*N)

Compiler
Level: Practionar Category: time_space_complexity

Question: 4

What is the time complexity of the following C++ code? 

int myFunction(int N, int M)
{
    for(int k=5; k<=N; k++)
    {
        cout<<k*2;
    }

    for(int l=5; l<=M; l++)
    {
        cout<<l*3;
    }
    return 0;
}

(A) O(N+M)
(B) O(N*M)
(C) O(N)
(D) O(M)

Compiler
Level: Practionar Category: time_space_complexity

Question: 5

What is the time complexity of the following C++ code? 

int myFunction(int N)
{

    for(int i=0; i<=N; i++)
    {
        for(int j=0; j<=i; j++)
        {
            cout<<"CppBuzz";
        }
    }
    return 0;
}

(A) O(N)
(B) O(Nlogn)
(C) O(N^2)
(D) O(N^3)

Compiler
Level: Practionar Category: time_space_complexity

Question: 6

What is the time complexity of the following C++ code? 

int myFunction(int N, int M)
{
    M=999;
    for(int i=0; i<=M; i=i+9;)
    {
        for(int j=0; j<=N; j++)
        {
            cout<<"CppBuzz";
        }
    }
    return 0;
}

(A) O(111*N)
(B) O(Nlogn)
(C) O(1)
(D) O(N)

Compiler
Level: Practionar Category: time_space_complexity

Question: 7

What is the time complexity of the following C++ code? 

int myFunction(int N, int M)
{
    M=0;
    for(int i=0; i<=N; i=i*M;)
    {     
        cout<<"CppBuzz";
    }
    return 0;
}

(A) O(N)
(B) O(logN)
(C) O(sqrt(N))
(D) O(∞)

Compiler
Level: Practionar Category: time_space_complexity

Question: 8

What is the time complexity to print all N elements of any integer array in C++?

(A) O(LogN)
(B) O(1)
(C) O(N)
(D) O(N longN)

Compiler
Level: Practionar Category: time_space_complexity

Question: 9

What is the time & Space complexity below the C++ function?

void reversePartofArray(int Arr[], int Start, int End)
{
    int tempStart = Start;
    int tempEnd = End;

    while(tempStart < tempEnd)
    {
        int temp = Arr[tempStart];
        Arr[tempStart] = Arr[tempEnd);
        Arr[tempEnd] = temp;

        tempStart += 1;
        tempEnd -= 1;
    }
}

(A) O(LogN) , O(N)
(B) O(N), O(N)
(C) O(N), O(1)
(D) O(N), O(0)

Compiler
Level: Practionar Category: time_space_complexity

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