Russian_Peasant_Algorithm.py

# Python Program to multiply two numbers using Russian Peasant method

# Function to multiply two numbers using Russian Peasant method


def russianPeasant(number1, number2):

    result = 0

    # While second number doesn't
    # become 1
    while (number2 > 0):

        # If second number becomes odd, add the first number to result
        if (number2 & 1):
            result = result + number1

        # Double the first number and halve the second number
        number1 = number1 << 1       # bitwise left shift operator
        number2 = number2 >> 1       # bitwise right shift operator

    return print("Result is", result)

# Driver code
number1 = int(input("Enter 1st Number:"))
number2 = int(input("Enter 2nd Number:"))
russianPeasant(number1, number2)

'''
Sample I/O:
    Input:
    Enter 1st Number:5
    Enter 2nd Number:5

    Output:
    Result is 25

Time complexity: Θ(1)
Space complexity: Θ(1)
'''