计数二进制表示的1的个数

def hamming_weight(n: int) -> int:
    count = 0
    while n:
        count += n & 1
        n >>= 1
    return count

# 示例
num = 0b00000000000000000000000000001011
print(hamming_weight(num))  # 输出: 3

def hamming_weight_bitwise(n: int) -> int:
    count = 0
    while n:
        n &= n - 1
        count += 1
    return count

# 示例
num = 0b00000000000000000000000000001011
print(hamming_weight_bitwise(num))  # 输出: 3

def hamming_weight_large_number(n: int) -> int:
    count = 0
    while n:
        n &= n - 1
        count += 1
    return count

# 示例
num = 0b11111111111111111111111111111101
print(hamming_weight_large_number(num))  # 输出: 31