/**
* Implements the all interval problem. See http://www.hakank.org/google_or_tools/all_interval.py
*/
private static void solve(int n) {
Solver solver = new Solver("AllInterval");
//
// variables
//
IntVar[] x = solver.makeIntVarArray(n, 0, n - 1, "x");
IntVar[] diffs = solver.makeIntVarArray(n - 1, 1, n - 1, "diffs");
//
// constraints
//
solver.addConstraint(solver.makeAllDifferent(x, true));
solver.addConstraint(solver.makeAllDifferent(diffs, true));
for (int k = 0; k < n - 1; k++) {
solver.addConstraint(
solver.makeEquality(
diffs[k], solver.makeAbs(solver.makeDifference(x[k + 1], x[k])).Var()));
}
// symmetry breaking
solver.addConstraint(solver.makeLess(x[0], x[n - 1]));
solver.addConstraint(solver.makeLess(diffs[0], diffs[1]));
//
// search
//
DecisionBuilder db = solver.makePhase(x, solver.CHOOSE_FIRST_UNBOUND, solver.ASSIGN_MIN_VALUE);
solver.newSearch(db);
//
// output
//
while (solver.nextSolution()) {
System.out.print("x : ");
for (int i = 0; i < n; i++) {
System.out.print(x[i].value() + " ");
}
System.out.print("\ndiffs: ");
for (int i = 0; i < n - 1; i++) {
System.out.print(diffs[i].value() + " ");
}
System.out.println("\n");
}
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.wall_time() + "ms");
}
/** Solves the N Queens problem. See http://www.hakank.org/google_or_tools/nqueens2.py */
private static void solve(int n, int num, int print) {
Solver solver = new Solver("NQueens");
System.out.println("n: " + n);
//
// variables
//
IntVar[] q = solver.makeIntVarArray(n, 0, n - 1, "q");
//
// constraints
//
solver.addConstraint(solver.makeAllDifferent(q, true));
IntVar b = solver.makeIntVar(1, 1, "b");
IntVar[] q1 = new IntVar[n];
IntVar[] q2 = new IntVar[n];
for (int i = 0; i < n; i++) {
for (int j = 0; j < i; j++) {
// // q[i]+i != q[j]+j
solver.addConstraint(
solver.makeNonEquality(solver.makeSum(q[i], i).Var(), solver.makeSum(q[j], j).Var()));
// q[i]-i != q[j]-j
solver.addConstraint(
solver.makeNonEquality(solver.makeSum(q[i], -i).Var(), solver.makeSum(q[j], -j).Var()));
}
}
//
// Solve
//
DecisionBuilder db =
solver.makePhase(q, solver.CHOOSE_MIN_SIZE_LOWEST_MAX, solver.ASSIGN_CENTER_VALUE);
solver.newSearch(db);
int c = 0;
while (solver.nextSolution()) {
if (print != 0) {
for (int i = 0; i < n; i++) {
System.out.print(q[i].value() + " ");
}
System.out.println();
}
c++;
if (num > 0 && c >= num) {
break;
}
}
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.wall_time() + "ms");
}