Reverse Bits of a Number in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize the result variable to zero.

DSA Python

def reverse_bits(n):
    result = [1]
    for _ in range(32):
        result = (result << 1) | (n & 1)
        n >>= 1
    return result

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

A1

Bn

C0

D-1

Attempts:

3 left

💡 Hint

Common Mistakes

Initializing result with 1 or n causes wrong output.

We start with result = 0 because we build the reversed bits from scratch.

2fill in blank

medium

Complete the code to extract the least significant bit of n.

DSA Python

def reverse_bits(n):
    result = 0
    for _ in range(32):
        bit = n [1] 1
        result = (result << 1) | bit
        n >>= 1
    return result

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

A&

B|

C^

D>>

Attempts:

3 left

💡 Hint

Common Mistakes

Using OR or XOR instead of AND causes wrong bit extraction.

Use bitwise AND & with 1 to get the last bit of n.

3fill in blank

hard

Fix the error in the code to shift n right by one bit.

DSA Python

def reverse_bits(n):
    result = 0
    for _ in range(32):
        bit = n & 1
        result = (result << 1) | bit
        n = n [1] 1
    return result

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

A<<

B|

C&

D>>

Attempts:

3 left

💡 Hint

Common Mistakes

Using left shift instead of right shift causes infinite loop or wrong bits.

Shift n right by 1 bit using >> to move to the next bit.

4fill in blank

hard

Fill both blanks to complete the loop that reverses bits.

DSA Python

def reverse_bits(n):
    result = 0
    for [1] in range([2]):
        bit = n & 1
        result = (result << 1) | bit
        n >>= 1
    return result

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

A_

Bi

C32

Dn

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable n in loop causes confusion.

Wrong loop count causes incomplete reversal.

Use a throwaway variable _ for the loop and iterate 32 times for 32 bits.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps numbers to their reversed bits.

DSA Python

reversed_bits = [1]: reverse_bits([2]) for [3] in range(5)

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

Ax

Dn

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names causes errors.

Using n instead of x breaks comprehension.

Use x as the variable and key, and call reverse_bits(x) for values.