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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.
"""

  toNum in Google CP Solver.

  Convert a number <-> array of int in a specific base.

  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
from ortools.constraint_solver import pywrapcp

#
# converts a number (s) <-> an array of integers (t) in the specific base.
#


def toNum(solver, t, s, base):
  tlen = len(t)
  solver.Add(
      s == solver.Sum([(base**(tlen - i - 1)) * t[i] for i in range(tlen)]))


# Create the solver.
solver = pywrapcp.Solver("toNum test")

# data
n = 4
base = 10

# declare variables
x = [solver.IntVar(0, n - 1, "x%i" % i) for i in range(n)]
y = solver.IntVar(0, 10**n - 1, "y")

#
# constraints
#
# solver.Add(solver.AllDifferent([x[i] for i in range(n)]))
solver.Add(solver.AllDifferent(x))
# solver.Add(x[0] > 0) # just for fun

toNum(solver, x, y, base)

#
# solution and search
#
solution = solver.Assignment()
solution.Add([x[i] for i in range(n)])
solution.Add(y)

collector = solver.AllSolutionCollector(solution)
solver.Solve(
    solver.Phase([x[i] for i in range(n)], 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(n)])
  print("y:", collector.Value(s, y))
  print()

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