45 lines
1.3 KiB
Python
45 lines
1.3 KiB
Python
def karatsuba(x, y):
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xLen = len(str(x))
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yLen = len(str(y))
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# handle single digit multiplication at the end of the iteration
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# this gives the loop an end, and gives us our final results
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if xLen == 1 or yLen == 1:
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return x * y
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else:
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n = max(xLen, yLen) // 2 # choose the longest length
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# calculate a, b, c, d for the iteration
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a = x // (10 ** n)
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b = x % (10 ** n)
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c = y // (10 ** n)
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d = y % (10 ** n)
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# run karatsuba to resolve ac and bd for the iteration
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ac = karatsuba(a, c)
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bd = karatsuba(b, d)
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# use karatsuba again to resolve adbc for the iteration
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adbc = karatsuba(a + b, c + d) - ac - bd
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# return the solution for the digit pairs of the iteration
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return ac * 10 ** (2 * n) + (adbc * 10 ** n) + bd
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# helper method to easily take in our inputs
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def takeInput(text):
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while True:
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try:
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x = int(input(text))
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return x
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except ValueError:
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print('You must input an integer!\n')
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num1 = takeInput('Please enter a number (:\n')
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num2 = takeInput('Please enter a number to multiply it by!\n')
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# Calculate the result and check if it is right
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res = num1 * num2
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karatsubaRes = karatsuba(num1, num2)
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print()
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print('Quadratic Result: ', res)
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print('Karatsuba Result: ', karatsubaRes)
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if res == karatsubaRes:
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print()
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print('The algorithm worked (:')
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