# 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.
"""
Crosswords in Google CP Solver.
This is a standard example for constraint logic programming. See e.g.
http://www.cis.temple.edu/~ingargio/cis587/readings/constraints.html
'''
We are to complete the puzzle
1 2 3 4 5
+---+---+---+---+---+ Given the list of words:
1 | 1 | | 2 | | 3 | AFT LASER
+---+---+---+---+---+ ALE LEE
2 | # | # | | # | | EEL LINE
+---+---+---+---+---+ HEEL SAILS
3 | # | 4 | | 5 | | HIKE SHEET
+---+---+---+---+---+ HOSES STEER
4 | 6 | # | 7 | | | KEEL TIE
+---+---+---+---+---+ KNOT
5 | 8 | | | | |
+---+---+---+---+---+
6 | | # | # | | # | The numbers 1,2,3,4,5,6,7,8 in the crossword
+---+---+---+---+---+ puzzle correspond to the words
that will start at those locations.
'''
The model was inspired by Sebastian Brand's Array Constraint cross word
example
http://www.cs.mu.oz.au/~sbrand/project/ac/
http://www.cs.mu.oz.au/~sbrand/project/ac/examples.pl
Also, see the following models:
* MiniZinc: http://www.hakank.org/minizinc/crossword.mzn
* Comet: http://www.hakank.org/comet/crossword.co
* ECLiPSe: http://hakank.org/eclipse/crossword2.ecl
* Gecode: http://hakank.org/gecode/crossword2.cpp
* SICStus: http://hakank.org/sicstus/crossword2.pl
* Zinc: http://hakank.org/minizinc/crossword2.zinc
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/
"""
from google.apputils import app
from ortools.constraint_solver import pywrapcp
def main(_):
# Create the solver.
solver = pywrapcp.Solver("Problem")
#
# data
#
alpha = "_abcdefghijklmnopqrstuvwxyz"
a = 1
b = 2
c = 3
d = 4
e = 5
f = 6
g = 7
h = 8
i = 9
j = 10
k = 11
l = 12
m = 13
n = 14
o = 15
p = 16
q = 17
r = 18
s = 19
t = 20
u = 21
v = 22
w = 23
x = 24
y = 25
z = 26
num_words = 15
word_len = 5
AA = [
[h, o, s, e, s], # HOSES
[l, a, s, e, r], # LASER
[s, a, i, l, s], # SAILS
[s, h, e, e, t], # SHEET
[s, t, e, e, r], # STEER
[h, e, e, l, 0], # HEEL
[h, i, k, e, 0], # HIKE
[k, e, e, l, 0], # KEEL
[k, n, o, t, 0], # KNOT
[l, i, n, e, 0], # LINE
[a, f, t, 0, 0], # AFT
[a, l, e, 0, 0], # ALE
[e, e, l, 0, 0], # EEL
[l, e, e, 0, 0], # LEE
[t, i, e, 0, 0] # TIE
]
num_overlapping = 12
overlapping = [
[0, 2, 1, 0], # s
[0, 4, 2, 0], # s
[3, 1, 1, 2], # i
[3, 2, 4, 0], # k
[3, 3, 2, 2], # e
[6, 0, 1, 3], # l
[6, 1, 4, 1], # e
[6, 2, 2, 3], # e
[7, 0, 5, 1], # l
[7, 2, 1, 4], # s
[7, 3, 4, 2], # e
[7, 4, 2, 4] # r
]
n = 8
# declare variables
A = {}
for I in range(num_words):
for J in range(word_len):
A[(I, J)] = solver.IntVar(0, 26, "A(%i,%i)" % (I, J))
A_flat = [A[(I, J)] for I in range(num_words) for J in range(word_len)]
E = [solver.IntVar(0, num_words, "E%i" % I) for I in range(n)]
#
# constraints
#
solver.Add(solver.AllDifferent(E))
for I in range(num_words):
for J in range(word_len):
solver.Add(A[(I, J)] == AA[I][J])
for I in range(num_overlapping):
# This is what I would do:
# solver.Add(A[(E[overlapping[I][0]], overlapping[I][1])] == A[(E[overlapping[I][2]], overlapping[I][3])])
# But we must use Element explicitly
solver.Add(
solver.Element(
A_flat, E[overlapping[I][0]] * word_len + overlapping[I][1]) ==
solver.Element(
A_flat, E[overlapping[I][2]] * word_len + overlapping[I][3]))
#
# solution and search
#
solution = solver.Assignment()
solution.Add(E)
# db: DecisionBuilder
db = solver.Phase(E + A_flat,
solver.INT_VAR_SIMPLE,
solver.ASSIGN_MIN_VALUE)
solver.NewSearch(db)
num_solutions = 0
while solver.NextSolution():
print E
print_solution(A, E, alpha, n, word_len)
num_solutions += 1
solver.EndSearch()
print
print "num_solutions:", num_solutions
print "failures:", solver.Failures()
print "branches:", solver.Branches()
print "WallTime:", solver.WallTime()
def print_solution(A, E, alpha, n, word_len):
for ee in range(n):
print "%i: (%2i)" % (ee, E[ee].Value()),
print "".join(["%s" % (alpha[A[ee, ii].Value()]) for ii in range(word_len)])
if __name__ == "__main__":
app.run()