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/*
 * This file is part of examples, http://choco-solver.org/
 *
 * Copyright (c) 2024, IMT Atlantique. All rights reserved.
 *
 * Licensed under the BSD 4-clause license.
 *
 * See LICENSE file in the project root for full license information.
 */
package org.chocosolver.examples.real;

import org.chocosolver.examples.AbstractProblem;
import org.chocosolver.solver.Model;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.solver.variables.RealVar;

import static org.chocosolver.solver.search.strategy.Search.inputOrderUBSearch;

/**
 * mozart-oz:

 * "A kid goes into a grocery store and buys four items. The cashier
 * charges $7.11, the kid pays and is about to leave when the cashier
 * calls the kid back, and says ''Hold on, I multiplied the four items
 * instead of adding them; I'll try again; Hah, with adding them the
 * price still comes to $7.11''. What were the prices of the four items?
 * 
 * The model is taken from: Christian Schulte, Gert Smolka, Finite Domain
 * Constraint Programming in Oz. A Tutorial. 2001."
 * 

 * 
 * This problem deals with large domains which result in integer overflows with classical constraints.
 * Thus, this example introduces a dedicated propagator which handles large value products.
 *
 * @author Charles Prud'homme, Jean-Guillaume Fages
 * @since 08/08/11
 */
public class Grocery extends AbstractProblem {


    IntVar[] itemCost;
    RealVar[] realitemCost;


    @Override
    public void buildModel() {
        model = new Model();
        double epsilon = 0.000001d;
        // 4 integer variables (price in cents)
        itemCost = model.intVarArray("item", 4, 1, 711, true);
        // views as real variables to be used by Ibex
        realitemCost = model.realIntViewArray(itemCost, epsilon);
        model.realIbexGenericConstraint("{0} + {1} + {2} + {3} = 711", realitemCost).post();
        model.realIbexGenericConstraint("{0} * {1}/100 * {2}/100 * {3}/100 = 711", realitemCost).post();
        // symmetry breaking
        model.realIbexGenericConstraint("{0} <= {1};{1} <= {2};{2} <= {3}", realitemCost).post();
    }

    @Override
    public void configureSearch() {
        // choco branching
        model.getSolver().showStatistics();
        model.getSolver().showSolutions();
        model.getSolver().setSearch(inputOrderUBSearch(itemCost));
        // ibex branching
        //		solver.set(new AssignmentInterval(realitemCost, new Cyclic(realitemCost), new RealDomainMiddle()));
    }

    @Override
    public void solve() {
        model.getSolver().solve();

        System.out.println("*******");
        int sum = 0;
        long prod = 1;
        for (int i = 0; i < 4; i++) {
            sum += (int) realitemCost[i].getUB();
            prod *= itemCost[i].getValue();
            System.out.println("item " + i + " : " + itemCost[i].getValue());
        }
        prod /= 1000000;
        System.out.println("sum = " + sum + " instead of 711");
        System.out.println("prod = " + prod + " instead of 711");
    }

    public static void main(String[] args) {
        new Grocery().execute(args);
    }
}