CodeSignal Technical Assessment Bit Manipulation and Mathematical Reasoning 1

Question 1

What does the expression `n & (n-1)` evaluate to when n is a power of 2?

Accepted Answer

0

Answer

n

Answer

1

Answer

n-1

Question 2

How do you check if the k-th bit (0-indexed) of integer n is set?

Accepted Answer

n & (1 << k)

Answer

n | (1 << k)

Answer

n ^ (1 << k)

Answer

n >> k & 0

Question 3

What is 5 XOR 3 in decimal?

Accepted Answer

6

Answer

2

Answer

7

Answer

8

Question 4

What does left-shifting an integer n by 1 position (`n << 1`) effectively compute?

Accepted Answer

n * 2

Answer

n / 2

Answer

n + 1

Answer

n - 1

Question 5

Which bit trick isolates the lowest set bit of integer n?

Accepted Answer

n & (-n)

Answer

n & (n+1)

Answer

n | (n-1)

Answer

n ^ (n-1)

Question 6

What is the result of `n ^ n` for any integer n?

Accepted Answer

0

Answer

n

Answer

1

Answer

2n