102 lines
2.6 KiB
C#
102 lines
2.6 KiB
C#
//
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// Copyright 2012 Hakan Kjellerstrand
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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using System;
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using Google.OrTools.ConstraintSolver;
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public class Diet
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{
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/**
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*
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* Solves the Diet problem
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*
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* See http://www.hakank.org/google_or_tools/diet1.py
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*
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*/
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private static void Solve()
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{
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Solver solver = new Solver("Diet");
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int n = 4;
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int[] price = { 50, 20, 30, 80}; // in cents
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// requirements for each nutrition type
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int[] limits = {500, 6, 10, 8};
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string[] products = {"A", "B", "C", "D"};
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// nutritions for each product
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int[] calories = {400, 200, 150, 500};
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int[] chocolate = {3, 2, 0, 0};
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int[] sugar = {2, 2, 4, 4};
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int[] fat = {2, 4, 1, 5};
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//
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// Decision variables
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//
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IntVar[] x = solver.MakeIntVarArray(n, 0, 100, "x");
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IntVar cost = x.ScalProd(price).Var();
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//
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// Constraints
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//
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// solver.Add(solver.MakeScalProdGreaterOrEqual(x, calories, limits[0]));
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solver.Add(x.ScalProd(calories) >= limits[0]);
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solver.Add(x.ScalProd(chocolate) >= limits[1]);
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solver.Add(x.ScalProd(sugar) >= limits[2]);
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solver.Add(x.ScalProd(fat) >= limits[3]);
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//
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// Objective
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//
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OptimizeVar obj = cost.Minimize(1);
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//
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// Search
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//
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DecisionBuilder db = solver.MakePhase(x,
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Solver.CHOOSE_PATH,
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Solver.ASSIGN_MIN_VALUE);
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solver.NewSearch(db, obj);
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while (solver.NextSolution()) {
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Console.WriteLine("cost: {0}", cost.Value());
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Console.WriteLine("Products: ");
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for(int i = 0; i < n; i++) {
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Console.WriteLine("{0}: {1}", products[i], x[i].Value());
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}
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Console.WriteLine();
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}
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Console.WriteLine("\nSolutions: {0}", solver.Solutions());
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Console.WriteLine("WallTime: {0}ms", solver.WallTime());
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Console.WriteLine("Failures: {0}", solver.Failures());
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Console.WriteLine("Branches: {0} ", solver.Branches());
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solver.EndSearch();
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}
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public static void Main(String[] args)
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{
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Solve();
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}
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}
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