104 lines
3.3 KiB
Python
104 lines
3.3 KiB
Python
# Copyright 2010-2011 Google
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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Cryptoarithmetic puzzle
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First attempt to solve equation CP + IS + FUN = TRUE
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where each letter represents a unique digit.
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This problem has 72 different solutions in base 10.
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Use of SolutionCollectors.
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Use of Solve().
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Use of gflags to choose the base.
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"""
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import gflags, sys
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from constraint_solver import pywrapcp
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from os import abort
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FLAGS = gflags.FLAGS
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gflags.DEFINE_integer('base', 10, "Base used to solve the problem.")
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gflags.DEFINE_bool('print_all_solutions', False, "Print all solutions?")
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def CPIsFun():
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# Constraint programming engine
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solver = pywrapcp.Solver('CP is fun!');
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kBase = gflags.FLAGS.base
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# Decision variables
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digits = range(0, kBase)
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digits_without_zero = digits[1:]
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c = solver.IntVar(digits_without_zero, 'C');
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p = solver.IntVar(digits, 'P');
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i = solver.IntVar(digits_without_zero, 'I');
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s = solver.IntVar(digits, 'S');
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f = solver.IntVar(digits_without_zero, 'F');
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u = solver.IntVar(digits, 'U');
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n = solver.IntVar(digits, 'N');
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t = solver.IntVar(digits_without_zero, 'T');
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r = solver.IntVar(digits, 'R');
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e = solver.IntVar(digits, 'E');
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# We need to group variables in a list to be able to use
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# the global constraint AllDifferent
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letters = [c, p, i, s, f, u, n, t, r, e]
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# Check if we have enough digits
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assert kBase >= len(letters)
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# Constraints
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solver.Add(solver.AllDifferent(letters))
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# CP + IS + FUN = TRUE
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term1 = solver.Sum([kBase*c, p])
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term2 = solver.Sum([kBase*i, s])
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term3 = solver.Sum([kBase*kBase*f, kBase*u, n])
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sum_terms = solver.Sum([term1, term2, term3])
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sum_value = solver.Sum([kBase*kBase*kBase*t, kBase*kBase*r, kBase*u, e])
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solver.Add(sum_terms == sum_value)
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all_solutions = solver.AllSolutionCollector()
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# Add the interesting variables to the SolutionCollector
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all_solutions.Add(letters)
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db = solver.Phase(letters, solver.INT_VAR_DEFAULT,
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solver.INT_VALUE_DEFAULT)
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solver.Solve(db, all_solutions)
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# Retrieve the solutions
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numberSolutions = all_solutions.SolutionCount()
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print "Number of solutions: ", numberSolutions
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if (gflags.FLAGS.print_all_solutions):
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for index in range(numberSolutions):
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print "C=", all_solutions.Value(index, c), " P=", all_solutions.Value(index, p), " I=", \
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all_solutions.Value(index, i), " S=", all_solutions.Value(index, s), " F=", all_solutions.Value(index, f), \
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" U=", all_solutions.Value(index, u), " N=", all_solutions.Value(index, n), " T=", all_solutions.Value(index, t), \
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" R=", all_solutions.Value(index, r), " E=", all_solutions.Value(index, e)
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return
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if __name__ == '__main__':
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try:
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FLAGS(sys.argv) # parse flags
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except gflags.FlagsError, e:
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print '%s\\nUsage: %s ARGS\\n%s' % (e, sys.argv[0], FLAGS)
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sys.exit(1)
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CPIsFun()
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