Choco Solver ICF约束，用于定义数组中最小和最大变量之间的距离

Question

我有一组Choco解算器IntVar变量，比如X1，X2，...，Xn。我需要定义一个强制执行规则的约束 - 最小和最大变量之间的距离（绝对差值）值应小于固定值，比如100，即| max（X1，... Xn） - min（X1， ..，XN）| ＆LT; 100。

有人可以帮忙吗？

Answer 1

你有IntConstraintFactory.distance()方法来准确地做到这一点。请参阅docs。

以下是执行您要求的实际代码：

Solver solver = new Solver();

int n = 10;
IntVar[] x = VariableFactory.boundedArray("x", n, 0, 500, solver);

IntVar min = VariableFactory.bounded("min", 0, 500, solver);
IntVar max = VariableFactory.bounded("max", 0, 500, solver);

solver.post(IntConstraintFactory.minimum(min, x));
solver.post(IntConstraintFactory.maximum(max, x));

solver.post(IntConstraintFactory.distance(min, max, "<", 100));

if (solver.findSolution()) {
    int solutions = 5;
    int nSol = 0;
    do {
        System.out.print("x: ");
        for (int i = 0; i < n; i++)
            System.out.print(x[i].getValue() + " ");
        System.out.println("\nmin = " + min.getValue() + ", max = " + max.getValue() + ", |min - max| = " + Math.abs(min.getValue() - max.getValue()) + "\n");

        nSol++;

        if (solutions > 0 && nSol >= solutions)
            break;
    } while (solver.nextSolution());

    System.out.println(nSol + " solutions found.");
} else {
    System.out.println("No solution found.");
}