104 lines
4.0 KiB
C#
104 lines
4.0 KiB
C#
// Copyright 2010-2022 Google LLC
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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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// [START program]
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// [START import]
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using System;
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using Google.OrTools.Graph;
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// [END import]
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public class BalanceMinFlow
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{
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static void Main()
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{
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// [START solver]
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// Instantiate a SimpleMinCostFlow solver.
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MinCostFlow minCostFlow = new MinCostFlow();
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// [END solver]
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// [START data]
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// Define the directed graph for the flow.
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int[] teamA = { 1, 3, 5 };
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int[] teamB = { 2, 4, 6 };
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// Define four parallel arrays: sources, destinations, capacities, and unit costs
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// between each pair.
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int[] startNodes = { 0, 0, 11, 11, 11, 12, 12, 12, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3,
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3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 8, 9, 10 };
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int[] endNodes = { 11, 12, 1, 3, 5, 2, 4, 6, 7, 8, 9, 10, 7, 8, 9, 10, 7, 8,
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9, 10, 7, 8, 9, 10, 7, 8, 9, 10, 7, 8, 9, 10, 13, 13, 13, 13 };
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int[] capacities = { 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 };
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int[] unitCosts = { 0, 0, 0, 0, 0, 0, 0, 0, 90, 76, 75, 70, 35, 85, 55, 65, 125, 95,
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90, 105, 45, 110, 95, 115, 60, 105, 80, 75, 45, 65, 110, 95, 0, 0, 0, 0 };
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int source = 0;
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int sink = 13;
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int tasks = 4;
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// Define an array of supplies at each node.
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int[] supplies = { tasks, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -tasks };
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// [END data]
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// [START constraints]
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// Add each arc.
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for (int i = 0; i < startNodes.Length; ++i)
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{
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int arc =
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minCostFlow.AddArcWithCapacityAndUnitCost(startNodes[i], endNodes[i], capacities[i], unitCosts[i]);
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if (arc != i)
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throw new Exception("Internal error");
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}
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// Add node supplies.
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for (int i = 0; i < supplies.Length; ++i)
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{
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minCostFlow.SetNodeSupply(i, supplies[i]);
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}
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// [END constraints]
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// [START solve]
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// Find the min cost flow.
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MinCostFlow.Status status = minCostFlow.Solve();
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// [END solve]
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// [START print_solution]
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if (status == MinCostFlow.Status.OPTIMAL)
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{
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Console.WriteLine("Total cost: " + minCostFlow.OptimalCost());
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Console.WriteLine("");
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for (int i = 0; i < minCostFlow.NumArcs(); ++i)
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{
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// Can ignore arcs leading out of source or into sink.
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if (minCostFlow.Tail(i) != source && minCostFlow.Tail(i) != 11 && minCostFlow.Tail(i) != 12 &&
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minCostFlow.Head(i) != sink)
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{
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// Arcs in the solution have a flow value of 1. Their start and end nodes
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// give an assignment of worker to task.
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if (minCostFlow.Flow(i) > 0)
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{
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Console.WriteLine("Worker " + minCostFlow.Tail(i) + " assigned to task " + minCostFlow.Head(i) +
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" Cost: " + minCostFlow.UnitCost(i));
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}
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}
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}
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}
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else
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{
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Console.WriteLine("Solving the min cost flow problem failed.");
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Console.WriteLine("Solver status: " + status);
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}
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// [END print_solution]
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}
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}
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// [END program]
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