8927b03942
Some of these imports are not used. The rest of them only import string to use the string.atoi function. But string.atoi(s) on a string input is identical to just int(s). See the docs: "deprecated since 2.0".
133 lines
3.0 KiB
Python
133 lines
3.0 KiB
Python
# Copyright 2010 Hakan Kjellerstrand hakank@bonetmail.com
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
"""
|
|
|
|
Place number puzzle Google CP Solver.
|
|
|
|
http://ai.uwaterloo.ca/~vanbeek/Courses/Slides/introduction.pdf
|
|
'''
|
|
Place numbers 1 through 8 on nodes
|
|
- each number appears exactly once
|
|
- no connected nodes have consecutive numbers
|
|
2 - 5
|
|
/ | X | \
|
|
1 - 3 - 6 - 8
|
|
\ | X | /
|
|
4 - 7
|
|
""
|
|
|
|
Compare with the following models:
|
|
* MiniZinc: http://www.hakank.org/minizinc/place_number.mzn
|
|
* Comet: http://www.hakank.org/comet/place_number_puzzle.co
|
|
* ECLiPSe: http://www.hakank.org/eclipse/place_number_puzzle.ecl
|
|
* SICStus Prolog: http://www.hakank.org/sicstus/place_number_puzzle.pl
|
|
* Gecode: http://www.hakank.org/gecode/place_number_puzzle.cpp
|
|
|
|
This model was created by Hakan Kjellerstrand (hakank@bonetmail.com)
|
|
Also see my other Google CP Solver models:
|
|
http://www.hakank.org/google_or_tools/
|
|
|
|
"""
|
|
|
|
import sys
|
|
from ortools.constraint_solver import pywrapcp
|
|
|
|
|
|
def main():
|
|
|
|
# Create the solver.
|
|
solver = pywrapcp.Solver("Place number")
|
|
|
|
# data
|
|
m = 32
|
|
n = 8
|
|
# Note: this is 1-based for compatibility (and lazyness)
|
|
graph = [
|
|
[1, 2],
|
|
[1, 3],
|
|
[1, 4],
|
|
[2, 1],
|
|
[2, 3],
|
|
[2, 5],
|
|
[2, 6],
|
|
[3, 2],
|
|
[3, 4],
|
|
[3, 6],
|
|
[3, 7],
|
|
[4, 1],
|
|
[4, 3],
|
|
[4, 6],
|
|
[4, 7],
|
|
[5, 2],
|
|
[5, 3],
|
|
[5, 6],
|
|
[5, 8],
|
|
[6, 2],
|
|
[6, 3],
|
|
[6, 4],
|
|
[6, 5],
|
|
[6, 7],
|
|
[6, 8],
|
|
[7, 3],
|
|
[7, 4],
|
|
[7, 6],
|
|
[7, 8],
|
|
[8, 5],
|
|
[8, 6],
|
|
[8, 7]
|
|
]
|
|
|
|
# declare variables
|
|
x = [solver.IntVar(1, n, "x%i" % i) for i in range(n)]
|
|
|
|
#
|
|
# constraints
|
|
#
|
|
solver.Add(solver.AllDifferent(x))
|
|
for i in range(m):
|
|
# Note: make 0-based
|
|
solver.Add(abs(
|
|
x[graph[i][0] - 1] - x[graph[i][1] - 1]) > 1)
|
|
|
|
# symmetry breaking
|
|
solver.Add(x[0] < x[n - 1])
|
|
|
|
#
|
|
# solution and search
|
|
#
|
|
solution = solver.Assignment()
|
|
solution.Add(x)
|
|
|
|
collector = solver.AllSolutionCollector(solution)
|
|
|
|
solver.Solve(solver.Phase(x,
|
|
solver.CHOOSE_FIRST_UNBOUND,
|
|
solver.ASSIGN_MIN_VALUE),
|
|
[collector])
|
|
|
|
num_solutions = collector.SolutionCount()
|
|
for s in range(num_solutions):
|
|
print "x:", [collector.Value(s, x[i]) for i in range(len(x))]
|
|
|
|
print
|
|
print "num_solutions:", num_solutions
|
|
print "failures:", solver.Failures()
|
|
print "branches:", solver.Branches()
|
|
print "WallTime:", solver.WallTime()
|
|
print
|
|
|
|
if __name__ == "__main__":
|
|
main()
|