/********************************************************
 * Xpress-BCL Java Example Problems
 * ================================
 *
 * file xbburg.java
 * ````````````````
 * Burglar problem, binary variable formulation.
 *
 * (c) 2008-2024 Fair Isaac Corporation
 * author: S.Heipcke, Jan. 2000, rev. Mar. 2011
 ********************************************************/

import com.dashoptimization.*;

public class xbburg {
  static final int NItems = 8; /* Number of items */

  /****DATA****/
  /* Item:                           1   2   3   4   5   6   7   8 */
  static final double[] VALUE = {15, 100, 90, 60, 40, 15, 10, 1};

  /* Value of items */
  static final double[] WEIGHT = {2, 20, 20, 30, 40, 30, 60, 10};
  /* Weight of items */
  static final double WTMAX = 102; /* Max weight allowed for haul */

  public static void main(String[] args) {
    try (XPRBprob p = new XPRBprob("Burglar"); /* Initialize BCL and create a new problem */
        XPRBexprContext context =
            new XPRBexprContext() /* Release XPRBexpr instances at end of block. */) {
      XPRBvar[] x;
      XPRBexpr lobj, kn;
      int i;

      /****VARIABLES****/
      x = new XPRBvar[NItems]; /* 1 if we take item i; 0 otherwise */
      for (i = 0; i < NItems; i++) x[i] = p.newVar("x", XPRB.BV);

      /****OBJECTIVE****/
      lobj = new XPRBexpr();
      for (i = 0; i < NItems; i++) lobj.add(x[i].mul(VALUE[i]));
      p.setObj(lobj); /* Set objective: maximize total value */

      /****CONSTRAINTS****/
      kn = new XPRBexpr();
      for (i = 0; i < NItems; i++) kn.add(x[i].mul(WEIGHT[i]));
      p.newCtr("WtMax", kn.lEql(WTMAX)); /* Weight restriction */

      /****SOLVING + OUTPUT****/
      p.setSense(XPRB.MAXIM); /* Choose the sense of the optimization */
      p.mipOptimize(""); /* Solve the MIP-problem */
      System.out.println("Objective: " + p.getObjVal()); /* Get objective value */

      for (i = 0; i < NItems; i++) /* Print out the solution */
        System.out.print(x[i].getName() + ":" + x[i].getSol() + " ");
      System.out.println();
    }
  }
}