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# Copyright 2010 Hakan Kjellerstrand hakank@gmail.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.
"""

  Grocery problem in Google CP Solver.

  From  Christian Schulte, Gert Smolka, Finite Domain
  http://www.mozart-oz.org/documentation/fdt/
  Constraint Programming in Oz. A Tutorial. 2001.
  '''
  A kid goes into a grocery store and buys four items. The cashier
  charges $7.11, the kid pays and is about to leave when the cashier
  calls the kid back, and says 'Hold on, I multiplied the four items
  instead of adding them; I'll try again; Hah, with adding them the
  price still comes to $7.11'. What were the prices of the four items?
  '''

  Compare with the following models:
  * MiniZinc: http://hakank.org/minizinc/grocery.mzn
  * Comet: http://hakank.org/comet/grocery.co
  * Zinc: http://hakank.org/minizinc/grocery.zinc

  This model was created by Hakan Kjellerstrand (hakank@gmail.com)
  Also see my other Google CP Solver models:
  http://www.hakank.org/google_or_tools/
"""
from __future__ import print_function
import sys

from ortools.constraint_solver import pywrapcp
from functools import reduce



# Create the solver.
solver = pywrapcp.Solver("Grocery")

#
# data
#
n = 4
c = 711

#
# declare variables
#
item = [solver.IntVar(0, c, "item[%i]" % i) for i in range(n)]

#
# constraints
#
solver.Add(solver.Sum(item) == c)
solver.Add(reduce(lambda x, y: x * y, item) == c * 100**3)

# symmetry breaking
for i in range(1, n):
  solver.Add(item[i - 1] < item[i])

#
# search and result
#
db = solver.Phase(item, solver.INT_VAR_SIMPLE, solver.INT_VALUE_SIMPLE)

solver.NewSearch(db)
num_solutions = 0
while solver.NextSolution():
  print("item:", [item[i].Value() for i in range(n)])
  print()
  num_solutions += 1

solver.EndSearch()

print()
print("num_solutions:", num_solutions)
print("failures:", solver.Failures())
print("branches:", solver.Branches())
print("WallTime:", solver.WallTime())