Check if Number is Power of Two in DSA Python - Practice Problems & Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this code snippet?

Given the function to check if a number is a power of two, what will be printed after calling print(is_power_of_two(16))?

DSA Python

def is_power_of_two(n):
    return n > 0 and (n & (n - 1)) == 0

print(is_power_of_two(16))

A True

B False

C 0

D TypeError

💡 Hint

Think about how binary AND works for powers of two.

A number that is a power of two has exactly one bit set in binary. The expression n & (n-1) clears the lowest set bit. If the result is zero, n was a power of two.

❓ Predict Output

intermediate

What is the output of this code snippet?

What will be printed after running this code?

DSA Python

def is_power_of_two(n):
    if n <= 0:
        return False
    while n % 2 == 0:
        n = n // 2
    return n == 1

print(is_power_of_two(18))

A True

B None

C False

D ZeroDivisionError

💡 Hint

Check if 18 can be divided by 2 repeatedly until 1.

18 is divisible by 2 once (18/2=9), but 9 is not divisible by 2, so the function returns False.

❓ Predict Output

advanced

What is the output of this code snippet?

What will be printed after running this code?

DSA Python

def is_power_of_two(n):
    return n > 0 and (n & (-n)) == n

print(is_power_of_two(32))

A True

B False

C TypeError

D 0

💡 Hint

Understand how n & (-n) isolates the lowest set bit.

For powers of two, n & (-n) equals n itself, so the function returns True.

🔧 Debug

advanced

What error does this code raise?

What error will occur when running this code?

DSA Python

def is_power_of_two(n):
    return n > 0 and (n & (n-1)) == 0

print(is_power_of_two(8))

A False

B SyntaxError

C TypeError

D True

💡 Hint

Check operator precedence and parentheses.

The expression (n & n-1) is parsed as (n & n) - 1 which is invalid syntax without parentheses.

🚀 Application

expert

How many numbers between 1 and 1000 (inclusive) are powers of two?

Count how many integers from 1 to 1000 are powers of two.

A 11

B 8

C 9

D 10

💡 Hint

List powers of two: 1, 2, 4, 8, ... up to 1000.

Powers of two up to 1000 are 1,2,4,8,16,32,64,128,256,512 (10 numbers).