Count how many 1s appear in the binary form of a number.
Determine if a number is an exact power of 2 (like 1, 2, 4, 8, 16, ...).
Find the number that appears only once in an array where every other number appears exactly twice.
Flip the binary representation of a 32-bit number so the first bit becomes the last and vice versa.
Count how many bits are different between two numbers.
AND all integers from m to n together. Find the result without looping through every number.