Solutions

# Count the number of times n & 1
# bit

# O(1) time (there's at most 32 bits), O(1) space

# Shifting the number
def hammingWeight(n: int) -> int:
    num_ones = 0
    while n > 0:
        num_ones += 1 if n & 1 else 0
        n = n >> 1
    return num_ones


# Removing the right-most 1 bit at each loop pass
# - Subtracting 1 from a number flips the rightmost 1 bit to 0 and turns all bits to its right into 1
# - Performing n & (n - 1) removes the rightmost 1 bit from n
def hammingWeight(n: int) -> int:
    res = 0
    while n:
        n &= n - 1
        res += 1
    return res


# Shifting the 1
def hammingWeight(n: int) -> int:
    res = 0
    for i in range(32):
        if (1 << i) & n:
            res += 1
    return res


def hammingWeight(n: int) -> int:
    return bin(n).count('1')
       


# The Hamming weight of a string is the number of symbols that are different from the zero-symbol of the alphabet used.
# It is thus equivalent to the Hamming distance from the all-zero string of the same length