Add AssignmentLinearAssignment in all supported languages

ortools/graph/samples/AssignmentLinearAssignment.cs

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+// Copyright 2010-2021 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.
+
+// [START program]
+// [START import]
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Google.OrTools.Graph;
+// [END import]
+
+public class AssignmentLinearAssignment
+{
+    static void Main()
+    {
+        // [START solver]
+        LinearSumAssignment assignment = new LinearSumAssignment();
+        // [END solver]
+
+        // [START data]
+        int[,] costs = {
+          {90, 76, 75, 70},
+          {35, 85, 55, 65},
+          {125, 95, 90, 105},
+          {45, 110, 95, 115},
+        };
+        int numWorkers = 4;
+        int[] allWorkers = Enumerable.Range(0, numWorkers).ToArray();
+        int numTasks = 4;
+        int[] allTasks = Enumerable.Range(0, numTasks).ToArray();
+        // [END data]
+
+        // [START constraints]
+        // Add each arc.
+        foreach (int w in allWorkers)
+        {
+          foreach (int t in allTasks)
+          {
+            if (costs[w,t] != 0)
+            {
+              assignment.AddArcWithCost(w, t, costs[w, t]);
+            }
+          }
+        }
+        // [END constraints]
+
+        // [START solve]
+        LinearSumAssignment.Status status = assignment.Solve();
+        // [END solve]
+
+        // [START print_solution]
+        if (status == LinearSumAssignment.Status.OPTIMAL)
+        {
+            Console.WriteLine($"Total cost: {assignment.OptimalCost()}.");
+            foreach (int worker in allWorkers)
+            {
+              Console.WriteLine(
+                  $"Worker {worker} assigned to task {assignment.RightMate(worker)}. " +
+                  $"Cost: {assignment.AssignmentCost(worker)}.");
+            }
+        }
+        else
+        {
+            Console.WriteLine("Solving the linear assignment problem failed.");
+            Console.WriteLine($"Solver status: {status}.");
+        }
+        // [END print_solution]
+    }
+}
+// [END program]

ortools/graph/samples/AssignmentLinearAssignment.java

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+// Copyright 2010-2021 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.
+
+// [START program]
+package com.google.ortools.graph.samples;
+// [START import]
+import com.google.ortools.Loader;
+import com.google.ortools.graph.LinearSumAssignment;
+import java.util.stream.IntStream;
+// [END import]
+
+/** Minimal Linear Sum Assignment. */
+public class AssignmentLinearAssignment {
+  public static void main(String[] args) throws Exception {
+    Loader.loadNativeLibraries();
+    // [START solver]
+    LinearSumAssignment assignment = new LinearSumAssignment();
+    // [END solver]
+
+    // [START data]
+    final int[][] costs = {
+          {90, 76, 75, 70},
+          {35, 85, 55, 65},
+          {125, 95, 90, 105},
+          {45, 110, 95, 115},
+    };
+    final int numWorkers = 4;
+    final int numTasks = 4;
+
+    final int[] allWorkers = IntStream.range(0, numWorkers).toArray();
+    final int[] allTasks = IntStream.range(0, numTasks).toArray();
+    // [END data]
+
+    // [START constraints]
+    // Add each arc.
+    for (int w : allWorkers) {
+      for (int t : allTasks) {
+        if (costs[w][t] != 0) {
+          assignment.addArcWithCost(w, t, costs[w][t]);
+        }
+      }
+    }
+    // [END constraints]
+
+    // [START solve]
+    LinearSumAssignment.Status status = assignment.solve();
+    // [END solve]
+
+    // [START print_solution]
+    if (status == LinearSumAssignment.Status.OPTIMAL) {
+      System.out.println("Total cost: " + assignment.getOptimalCost());
+      for (int worker : allWorkers) {
+            System.out.println("Worker " + worker +
+                " assigned to task " + assignment.getRightMate(worker) +
+                ". Cost: " + assignment.getAssignmentCost(worker));
+      }
+    } else {
+      System.out.println("Solving the min cost flow problem failed.");
+      System.out.println("Solver status: " + status);
+    }
+    // [END print_solution]
+  }
+
+  private AssignmentLinearAssignment() {}
+}
+// [END program]

ortools/graph/samples/assignment_linear_assignment.cc

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+// Copyright 2010-2021 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.
+
+// [START program]
+// [START import]
+#include <cstdint>
+#include <string>
+#include <vector>
+#include <numeric>
+
+#include "ortools/graph/assignment.h"
+// [END import]
+
+namespace operations_research {
+// MinCostFlow simple interface example.
+void AssignmentLinearAssignment() {
+  // [START solver]
+  SimpleLinearSumAssignment assignment;
+  // [END solver]
+
+  // [START data]
+  const int num_workers = 4;
+  std::vector<int> all_workers(num_workers);
+  std::iota(all_workers.begin(), all_workers.end(), 0);
+
+  const int num_tasks = 4;
+  std::vector<int> all_tasks(num_tasks);
+  std::iota(all_tasks.begin(), all_tasks.end(), 0);
+
+  const std::vector<std::vector<int>> costs = {{
+    {{90, 76, 75, 70}}, // Worker 0
+    {{35, 85, 55, 65}}, // Worker 1
+    {{125, 95, 90, 105}}, // Worker 2
+    {{45, 110, 95, 115}}, // Worker 3
+  }};
+  // [END data]
+
+  // [START constraints]
+  for (int w: all_workers) {
+    for (int t: all_tasks) {
+      if (costs[w][t]) {
+        assignment.AddArcWithCost(w, t, costs[w][t]);
+      }
+    }
+  }
+  // [END constraints]
+
+  // [START solve]
+  SimpleLinearSumAssignment::Status status = assignment.Solve();
+  // [END solve]
+
+  // [START print_solution]
+  if (status == SimpleLinearSumAssignment::OPTIMAL) {
+    LOG(INFO) << "Total cost: " << assignment.OptimalCost();
+    for (int worker: all_workers) {
+      LOG(INFO)
+        << "Worker " << std::to_string(worker)
+        << " assigned to task "  << std::to_string(assignment.RightMate(worker))
+        << ". Cost: "  << std::to_string(assignment.AssignmentCost(worker)) << ".";
+    }
+  } else {
+    LOG(INFO) << "Solving the linear assignment problem failed.";
+  }
+  // [END print_solution]
+}
+
+}  // namespace operations_research
+
+int main() {
+  operations_research::AssignmentLinearAssignment();
+  return EXIT_SUCCESS;
+}
+// [END program]