Task: Subset sum problem




Go: package main

import "fmt"

type ww struct {
    word   string
    weight int
}

var input = []*ww{
    {"alliance", -624},
    {"archbishop", -915},
    {"balm", 397},
    {"bonnet", 452},
    {"brute", 870},
    {"centipede", -658},
    {"cobol", 362},
    {"covariate", 590},
    {"departure", 952},
    {"deploy", 44},
    {"diophantine", 645},
    {"efferent", 54},
    {"elysee", -326},
    {"eradicate", 376},
    {"escritoire", 856},
    {"exorcism", -983},
    {"fiat", 170},
    {"filmy", -874},
    {"flatworm", 503},
    {"gestapo", 915},
    {"infra", -847},
    {"isis", -982},
    {"lindholm", 999},
    {"markham", 475},
    {"mincemeat", -880},
    {"moresby", 756},
    {"mycenae", 183},
    {"plugging", -266},
    {"smokescreen", 423},
    {"speakeasy", -745},
    {"vein", 813},
}

type sss struct {
    subset []*ww
    sum    int
}

func main() {
    ps := []sss{{nil, 0}}
    for _, i := range input {
        pl := len(ps)
        for j := 0; j < pl; j++ {
            subset := append([]*ww{i}, ps[j].subset...)
            sum := i.weight + ps[j].sum
            if sum == 0 {
                fmt.Println("this subset sums to 0:")
                for _, i := range subset {
                    fmt.Println(*i)
                }
                return
            }
            ps = append(ps, sss{subset, sum})
        }
    }
    fmt.Println("no subset sums to 0")
}


Java: public class SubsetSum {
    private static class Item {
        private String word;
        private int weight;

        public Item(String word, int weight) {
            this.word = word;
            this.weight = weight;
        }

        @Override
        public String toString() {
            return String.format("(%s, %d)", word, weight);
        }
    }

    private static Item[] items = new Item[]{
        new Item("alliance", -624),
        new Item("archbishop", -915),
        new Item("balm", 397),
        new Item("bonnet", 452),
        new Item("brute", 870),
        new Item("centipede", -658),
        new Item("cobol", 362),
        new Item("covariate", 590),
        new Item("departure", 952),
        new Item("deploy", 44),
        new Item("diophantine", 645),
        new Item("efferent", 54),
        new Item("elysee", -326),
        new Item("eradicate", 376),
        new Item("escritoire", 856),
        new Item("exorcism", -983),
        new Item("fiat", 170),
        new Item("filmy", -874),
        new Item("flatworm", 503),
        new Item("gestapo", 915),
        new Item("infra", -847),
        new Item("isis", -982),
        new Item("lindholm", 999),
        new Item("markham", 475),
        new Item("mincemeat", -880),
        new Item("moresby", 756),
        new Item("mycenae", 183),
        new Item("plugging", -266),
        new Item("smokescreen", 423),
        new Item("speakeasy", -745),
        new Item("vein", 813),
    };

    private static final int n = items.length;
    private static final int[] indices = new int[n];
    private static int count = 0;

    private static final int LIMIT = 5;

    private static void zeroSum(int i, int w) {
        if (i != 0 && w == 0) {
            for (int j = 0; j < i; ++j) {
                System.out.printf("%s ", items[indices[j]]);
            }
            System.out.println("\n");
            if (count < LIMIT) count++;
            else return;
        }
        int k = (i != 0) ? indices[i - 1] + 1 : 0;
        for (int j = k; j < n; ++j) {
            indices[i] = j;
            zeroSum(i + 1, w + items[j].weight);
            if (count == LIMIT) return;
        }
    }

    public static void main(String[] args) {
        System.out.printf("The weights of the following %d subsets add up to zero:\n\n", LIMIT);
        zeroSum(0, 0);
    }
}