Task: Subset sum problem



C#: using System;
using System.Collections.Generic;

namespace SubsetSum {
    class Item {
        public Item(string word, int weight) {
            Word = word;
            Weight = weight;
        }

        public string Word { get; set; }
        public int Weight { get; set; }

        public override string ToString() {
            return string.Format("({0}, {1})", Word, Weight);
        }
    }

    class Program {
        private static readonly List<Item> items = new List<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 readonly int n = items.Count;
        private static readonly int LIMIT = 5;

        private static int[] indices = new int[n];
        private static int count = 0;

        private static void ZeroSum(int i, int w) {
            if (i != 0 && w == 0) {
                for (int j = 0; j < i; j++) {
                    Console.Write("{0} ", items[indices[j]]);
                }
                Console.WriteLine("\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;
            }
        }

        static void Main(string[] args) {
            Console.WriteLine("The weights of the following {0} subsets add up to zero:\n", LIMIT);
            ZeroSum(0, 0);
        }
    }
}





Python: words = { 
	"alliance": -624,	"archbishop": -925,	"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
}

neg = 0
pos = 0
for (w,v) in words.iteritems():
	if v > 0: pos += v
	else:     neg += v

sums = [0] * (pos - neg + 1)

for (w,v) in words.iteritems():
	s = sums[:]
	if not s[v - neg]: s[v - neg] = (w,)

	for (i, w2) in enumerate(sums):
		if w2 and not s[i + v]:
			s[i + v] = w2 + (w,)

	sums = s
	if s[-neg]:
		for x in s[-neg]:
			print(x, words[x])
		break