Solutions

# The bits in the reversed number are in the 31-i position, so we check if the bit in the i position of n is set, and if it is, we set the bit in the 31-i position of res.
# bit

# O(1) time, O(1) space
def reverseBits(self, n: int) -> int:
    res = 0
    for i in range(32):
        mask = 1 << i
        isset = mask & n
        if isset:
            res |= 1 << (31 - i)

    return res