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olympic

examples/notebook/contrib/olympic.ipynb

2016-063.3 KB
Original Source
Copyright 2025 Google LLC.

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.

olympic

<table align="left"> <td> <a href="https://colab.research.google.com/github/google/or-tools/blob/main/examples/notebook/contrib/olympic.ipynb">Run in Google Colab</a> </td> <td> <a href="https://github.com/google/or-tools/blob/main/examples/contrib/olympic.py">View source on GitHub</a> </td> </table>

First, you must install ortools package in this colab.

python
%pip install ortools

Olympic puzzle in Google CP Solver.

Benchmark for Prolog (BProlog) ''' File : olympic.pl Author : Neng-Fa ZHOU Date : 1993

Purpose: solve a puzzle taken from Olympic Arithmetic Contest

Given ten variables with the following configuration:

             X7   X8   X9   X10

                X4   X5   X6

                   X2   X3

                      X1

We already know that X1 is equal to 3 and want to assign each variable with a different integer from {1,2,...,10} such that for any three variables Xi Xj

                       Xk

the following constraint is satisfied:

                  |Xi-Xj| = Xk

'''

Compare with the following models:

This model was created by Hakan Kjellerstrand ([email protected]) Also see my other Google CP Solver models: http://www.hakank.org/google_or_tools/

python
import sys
from ortools.constraint_solver import pywrapcp


def minus(solver, x, y, z):
  solver.Add(z == abs(x - y))


def main():

  # Create the solver.
  solver = pywrapcp.Solver('Olympic')

  #
  # data
  #
  n = 10

  #
  # declare variables
  #
  Vars = [solver.IntVar(1, n, 'Vars[%i]' % i) for i in range(n)]
  X1, X2, X3, X4, X5, X6, X7, X8, X9, X10 = Vars

  #
  # constraints
  #
  solver.Add(solver.AllDifferent(Vars))

  solver.Add(X1 == 3)
  minus(solver, X2, X3, X1)
  minus(solver, X4, X5, X2)
  minus(solver, X5, X6, X3)
  minus(solver, X7, X8, X4)
  minus(solver, X8, X9, X5)
  minus(solver, X9, X10, X6)

  #
  # solution and search
  #
  db = solver.Phase(Vars, solver.INT_VAR_SIMPLE, solver.INT_VALUE_DEFAULT)

  solver.NewSearch(db)

  num_solutions = 0
  while solver.NextSolution():
    num_solutions += 1
    print('Vars:', [Vars[i].Value() for i in range(n)])

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


main()