Selecting A combination of minimum cost

Question

I have data of different items in a different restaurants

    Rest    Item     Price
    ----------------------
    ABC     dosa      14
    ABC     idly             


        

Answer 1

try

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class Mult {
    /**
     * @param args
     */
    public static void main(String[] args) {
        Map> xx = new HashMap>();
        xx.put("ABC",new ArrayList());
        xx.get("ABC").add(new X("", 0));
        xx.get("ABC").add(new X("dosa", 14));
        xx.get("ABC").add(new X("idly", 30));
        xx.get("ABC").add(new X("idly+upma", 25));


        xx.put("123",new ArrayList());
        xx.get("123").add(new X("", 0));
        xx.get("123").add(new X("dosa", 30));
        xx.get("123").add(new X("idly", 7));
        xx.get("123").add(new X("upma", 12));


        xx.put("XYZ",new ArrayList());
        xx.get("XYZ").add(new X("", 0));
        xx.get("XYZ").add(new X("dosa", 20));
        xx.get("XYZ").add(new X("idly", 12));
        xx.get("XYZ").add(new X("upma", 20));
        xx.get("XYZ").add(new X("dosa+upma", 30));
        xx.get("XYZ").add(new X("dosa+idly+upma", 40));

        String[] t = {
                "dosaidlyupma",
                "idlydosaupma",
                "upmaidlydosa",
                "dosaupmaidly",
                "upmadosaidly",
                "idlyupmadosa"};
        Set targets = new HashSet(Arrays.asList(t));

        Map best = new HashMap();

        for(String restaurant:xx.keySet()){
            best.put(restaurant, Integer.MAX_VALUE);
            String combo = null;
            for(X a:xx.get(restaurant)){
                int deal = a.price;
                combo = a.item;
                for(X b:xx.get(restaurant)){
                    deal = deal + b.price;
                    combo = combo + "+" + b.item;
                    for(X c:xx.get(restaurant)){
                        deal = deal + c.price;
                        combo = combo + "+" + c.item;
                        if (targets.contains(combo.replaceAll("\\+", ""))){
//                          System.out.println(restaurant+"\t"+combo.replaceAll("\\+", "")+"\t"+deal);
                            if (best.get(restaurant) > deal){
                                best.put(restaurant, deal);                 
                            }
                        }
                    }
                }
            }
        }

        System.out.println(best);
    }

}

will give you

{XYZ=40, ABC=39, 123=49}

it's the old good brute force approach.

not the best one, but for this small set, it works.