Check if Number is Power of Two in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if a number is a power of two using bitwise AND.

DSA C

int isPowerOfTwo(unsigned int n) {
    return n && !(n & (n [1] 1));
}

Drag options to blanks, or click blank then click option'

A+

B-

C<<

D>>

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition or shift operators instead of subtraction.

Not checking if n is zero before the bitwise operation.

The expression n & (n - 1) clears the lowest set bit. If the result is zero, n is a power of two.

2fill in blank

medium

Complete the code to return 1 if n is power of two, else 0.

DSA C

int isPowerOfTwo(unsigned int n) {
    if (n == 0) return 0;
    return (n & (n [1] 1)) == 0;
}

Drag options to blanks, or click blank then click option'

A+

B<<

C-

D>>

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition instead of subtraction.

Not handling the zero case.

Subtracting 1 from n flips the lowest set bit and all bits after it. The bitwise AND with n should be zero for powers of two.

3fill in blank

hard

Fix the error in the code to correctly check if n is power of two.

DSA C

int isPowerOfTwo(unsigned int n) {
    if (n == 0) return 0;
    return (n & (n [1] 1)) == 0;
}

Drag options to blanks, or click blank then click option'

A-

B/

C+

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition or multiplication instead of subtraction.

Not checking for zero input.

The correct operation is subtraction. Using addition or multiplication will not correctly clear the lowest set bit.

4fill in blank

hard

Fill both blanks to create a function that returns 1 if n is power of two, else 0.

DSA C

int isPowerOfTwo(unsigned int n) {
    if (n == [1]) return 0;
    return (n & (n [2] 1)) == 0;
}

Drag options to blanks, or click blank then click option'

A0

B1

C+

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Checking if n equals 1 instead of 0.

Using addition instead of subtraction.

We check if n is zero first, then use subtraction in the bitwise AND expression.

5fill in blank

hard

Fill all three blanks to complete the function that returns 1 if n is power of two, else 0.

DSA C

int isPowerOfTwo(unsigned int n) {
    if (n == [1]) return [2];
    return (n & (n [3] 1)) == 0;
}

Drag options to blanks, or click blank then click option'

A1

B0

C-

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Returning 1 when n is zero.

Using addition instead of subtraction.

Check if n is zero and return 0. Then use subtraction in the bitwise AND check.