Solution to MindYourDecisions video https://www.youtube.com/watch?v=9dyK_op-Ocw with constraint programming

incredible_factorial.py

from constraint import *


def fact(n):
    f = 1
  
    for i in range(1,n+1): 
        f = f * i 
    return f


problem = Problem()

# you should choose these wisely
problem.addVariable('a', list(range(0, 10)))
problem.addVariable('b', list(range(0, 10)))
problem.addVariable('c', list(range(0, 10)))

def func(a, b, c):
    fact_a = fact(a)
    fact_b = fact(b)
    return fact_a*fact_b == fact_a + fact_b + fact(c)

problem.addConstraint(func)

print(problem.getSolutions())
# prints [{'a': 3, 'b': 3, 'c': 4}]