[python] Bitwise Operations

def bitwise_and(num1, num2):

	result = "" # the result of the bitwise and operation

	while num1 > 0 or num2 > 0:
		# num % 2  != 0 implies a 1-bit in the lowest position
		if num1 % 2 != 0 and num2 % 2 != 0: 
			result = "1" + result # both bits are 1, so 1 & 1 == 1, append 1 to result
		else:
			result = "0" + result# at least one 0 bit, 1 & 0 == 0, 0 & 0 == 0, append 0

		num1 = num1 >> 1 # drop the last bit
		num2 = num2 >> 1 # drop the last bit

	return int(result,2) # return an int representation of the result binary string

#divmod version

def divmod_and(x, y):
    z = 0
    p = 1
    while x or y:
        x, xd = divmod(x, 2)
        y, yd = divmod(y, 2)
        z = p * xd * yd + z
        p <<= 1

    return z

# manual mod and divide for clarity

def bitwise_and(x, y):
    result = 0
    power = 1
    while x or y:
        bit = x % 2 * y % 2 # both bits on == 1
        result = bit * power + result
        x /= 2
        y /= 2
        power <<= 1

    return result