Move java examples

examples/java/CoinsGrid.java

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+// Copyright 2011 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.
+import java.io.*;
+import java.util.*;
+import java.text.*;
+
+import com.google.ortools.constraintsolver.DecisionBuilder;
+import com.google.ortools.constraintsolver.IntVar;
+import com.google.ortools.constraintsolver.Solver;
+import com.google.ortools.constraintsolver.OptimizeVar;
+
+
+public class CoinsGrid {
+
+  static {
+    System.loadLibrary("jniortools");
+  }
+
+  /**
+   *
+   * Solves the Coins Grid problem.
+   * See http://www.hakank.org/google_or_tools/coins_grid.py
+   *
+   */
+  private static void solve() {
+    Solver solver = new Solver("CoinsGrid");
+
+    //
+    // data
+    //
+    int n = 31;
+    int c = 14;
+
+    //
+    // variables
+    //
+    IntVar[][] x = new IntVar[n][n];
+    IntVar[] x_flat = new IntVar[n * n];
+
+    for(int i = 0; i < n; i++) {
+      for(int j = 0; j < n; j++) {
+        x[i][j] = solver.makeIntVar(0, 1, "x[" + i + "," + j + "]");
+        x_flat[i * n + j] = x[i][j];
+      }
+    }
+
+    //
+    // constraints
+    //
+
+    // sum row/columns == c
+    for(int i = 0; i < n; i++) {
+      IntVar[] row = new IntVar[n];
+      IntVar[] col = new IntVar[n];
+      for(int j = 0; j < n; j++) {
+        row[j] = x[i][j];
+        col[j] = x[j][i];
+      }
+      solver.addConstraint(solver.makeSumEquality(row, c));
+      solver.addConstraint(solver.makeSumEquality(col, c));
+    }
+
+    // quadratic horizonal distance
+    IntVar[] obj_tmp = new IntVar[n * n];
+    for(int i = 0; i < n; i++) {
+      for(int j = 0; j < n; j++) {
+        obj_tmp[i * n + j] =
+          solver.makeProd(x[i][j],(i - j) * (i - j)).var();
+      }
+    }
+    IntVar obj_var = solver.makeSum(obj_tmp).var();
+
+    //
+    // objective
+    //
+    OptimizeVar obj = solver.makeMinimize(obj_var, 1);
+
+    //
+    // search
+    //
+    DecisionBuilder db = solver.makePhase(x_flat,
+                                          solver.CHOOSE_FIRST_UNBOUND,
+                                          solver.ASSIGN_MAX_VALUE);
+
+    solver.newSearch(db, obj);
+
+    //
+    // output
+    //
+    while (solver.nextSolution()) {
+      System.out.println("obj_var: " + obj_var.value());
+      for(int i = 0; i < n; i++) {
+        for(int j = 0; j < n; j++) {
+          System.out.print(x[i][j].value() + " ");
+        }
+        System.out.println();
+      }
+      System.out.println();
+    }
+    solver.endSearch();
+
+    // Statistics
+    System.out.println();
+    System.out.println("Solutions: " + solver.solutions());
+    System.out.println("Failures: " + solver.failures());
+    System.out.println("Branches: " + solver.branches());
+    System.out.println("Wall time: " + solver.wallTime() + "ms");
+  }
+
+  public static void main(String[] args) throws Exception {
+    CoinsGrid.solve();
+  }
+}