Bit Manipulation Basics AND OR XOR NOT Left Right Shift in DSA Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the AND (&) bitwise operator do between two bits?

The AND operator returns 1 only if both bits are 1; otherwise, it returns 0.<br>Example: 1 & 1 = 1, 1 & 0 = 0, 0 & 0 = 0.

beginner

Explain the OR (|) bitwise operator with an example.

The OR operator returns 1 if at least one of the bits is 1; otherwise, it returns 0.<br>Example: 1 | 0 = 1, 0 | 0 = 0, 1 | 1 = 1.

beginner

What is the result of XOR (^) between two bits?

XOR returns 1 if the bits are different, and 0 if they are the same.<br>Example: 1 ^ 0 = 1, 1 ^ 1 = 0, 0 ^ 0 = 0.

intermediate

Describe the NOT (~) bitwise operator.

NOT flips each bit: 1 becomes 0, and 0 becomes 1.<br>Example: ~1 (in 1-bit) = 0, ~0 = 1.<br>In computers, it also changes the sign due to two's complement representation.

intermediate

What happens when you perform a left shift (<<) and right shift (>>) on a binary number?

Left shift (<<) moves bits to the left, adding zeros on the right, effectively multiplying by 2 for each shift.<br>Right shift (>>) moves bits to the right, discarding bits on the right, effectively dividing by 2 for each shift.<br>Example: 4 (0100) << 1 = 8 (1000), 4 >> 1 = 2 (0010).

What is the result of 5 & 3 in binary? (5 = 0101, 3 = 0011)

A 0101 (5)

B 0011 (3)

C 0001 (1)

D 0111 (7)

AND compares bits: 0&0=0,1&1=1, so 0101 & 0011 = 0001 which is 1.

Which operator returns 1 only when bits are different?

A AND (&)

B NOT (~)

C OR (|)

D XOR (^)

XOR returns 1 if bits differ, 0 if they are the same.

What does the expression ~0 evaluate to in a 4-bit system?

A 1111 (-1 in two's complement)

B 0000 (0)

C 1110 (14)

D 0001 (1)

NOT flips all bits: ~0000 = 1111, which is -1 in two's complement.

What is the decimal result of 6 << 2?

A 24

B 12

C 3

D 48

Left shift by 2 multiplies by 2^2=4, so 6*4=24.

Which bitwise operator would you use to clear specific bits (set them to 0)?

A OR (|) with mask

B AND (&) with mask

C XOR (^) with mask

D NOT (~)

AND with a mask having 0s clears bits; 1s keep bits unchanged.

Explain how the XOR operator works and give a real-life example where it might be useful.

Think about switching a light on/off using XOR.

Describe what happens to a binary number when you perform a left shift and a right shift.

Imagine moving digits in a number to the left or right.