Move java examples

examples/java/Sudoku.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;
+
+public class Sudoku {
+
+  static {
+    System.loadLibrary("jniortools");
+  }
+
+
+  /**
+   *
+   * Solves a Sudoku problem.
+   *
+   */
+  private static void solve() {
+
+    Solver solver = new Solver("Sudoku");
+
+    int cell_size = 3;
+    int n = cell_size * cell_size;
+
+    // 0 marks an unknown value
+    int[][] initial_grid = new int[][] {{0, 6, 0, 0, 5, 0, 0, 2, 0},
+                                        {0, 0, 0, 3, 0, 0, 0, 9, 0},
+                                        {7, 0, 0, 6, 0, 0, 0, 1, 0},
+                                        {0, 0, 6, 0, 3, 0, 4, 0, 0},
+                                        {0, 0, 4, 0, 7, 0, 1, 0, 0},
+                                        {0, 0, 5, 0, 9, 0, 8, 0, 0},
+                                        {0, 4, 0, 0, 0, 1, 0, 0, 6},
+                                        {0, 3, 0, 0, 0, 8, 0, 0, 0},
+                                        {0, 2, 0, 0, 4, 0, 0, 5, 0}};
+
+    //
+    // variables
+    //
+    IntVar[][] grid = new IntVar[n][n];
+    IntVar[] grid_flat = new IntVar[n * n];
+
+    for(int i = 0; i < n; i++) {
+      for(int j = 0; j < n; j++) {
+        grid[i][j] = solver.makeIntVar(1, 9, "grid[" + i +"," + j + "]");
+        grid_flat[i * n + j] = grid[i][j];
+      }
+    }
+
+    //
+    // constraints
+    //
+
+    // init and rows
+    for(int i = 0; i < n; i++) {
+      IntVar[] row = new IntVar[n];
+      for(int j = 0; j < n; j++) {
+        if (initial_grid[i][j] > 0) {
+          solver.addConstraint(
+              solver.makeEquality(grid[i][j], initial_grid[i][j]));
+        }
+        row[j] = grid[i][j];
+      }
+      solver.addConstraint(solver.makeAllDifferent(row));
+    }
+
+    // columns
+    for(int j = 0; j < n; j++) {
+      IntVar[] col = new IntVar[n];
+      for(int i = 0; i < n; i++) {
+        col[i] = grid[i][j];
+      }
+      solver.addConstraint(solver.makeAllDifferent(col));
+    }
+
+    // cells
+    for(int i = 0; i < cell_size; i++) {
+      for(int j = 0; j < cell_size; j++) {
+        IntVar[] cell = new IntVar[n];
+        for(int di = 0; di < cell_size; di++) {
+          for(int dj = 0; dj < cell_size; dj++) {
+            cell[di * cell_size + dj] =
+              grid[i * cell_size + di][j * cell_size + dj];
+          }
+        }
+        solver.addConstraint(solver.makeAllDifferent(cell));
+      }
+    }
+
+    //
+    // Search
+    //
+    DecisionBuilder db = solver.makePhase(grid_flat,
+                                          solver.INT_VAR_SIMPLE,
+                                          solver.INT_VALUE_SIMPLE);
+
+    solver.newSearch(db);
+
+    while (solver.nextSolution()) {
+      for(int i = 0; i < n; i++) {
+        for(int j = 0; j < n; j++) {
+          System.out.print(grid[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 {
+    Sudoku.solve();
+  }
+}