try: xrange except: xrange = range def totalvalue(comb): ' Totalise a particular combination of items' totwt = totval = 0 for item, wt, val in comb: totwt += wt totval += val return (totval, -totwt) if totwt <= 400 else (0, 0) items = ( ("map", 9, 150), ("compass", 13, 35), ("water", 153, 200), ("sandwich", 50, 160), ("glucose", 15, 60), ("tin", 68, 45), ("banana", 27, 60), ("apple", 39, 40), ("cheese", 23, 30), ("beer", 52, 10), ("suntan cream", 11, 70), ("camera", 32, 30), ("t-shirt", 24, 15), ("trousers", 48, 10), ("umbrella", 73, 40), ("waterproof trousers", 42, 70), ("waterproof overclothes", 43, 75), ("note-case", 22, 80), ("sunglasses", 7, 20), ("towel", 18, 12), ("socks", 4, 50), ("book", 30, 10), ) def knapsack01_dp(items, limit): table = [[0 for w in range(limit + 1)] for j in xrange(len(items) + 1)] for j in xrange(1, len(items) + 1): item, wt, val = items[j-1] for w in xrange(1, limit + 1): if wt > w: table[j][w] = table[j-1][w] else: table[j][w] = max(table[j-1][w], table[j-1][w-wt] + val) result = [] w = limit for j in range(len(items), 0, -1): was_added = table[j][w] != table[j-1][w] if was_added: item, wt, val = items[j-1] result.append(items[j-1]) w -= wt return result bagged = knapsack01_dp(items, 400) print("Bagged the following items\n " + '\n '.join(sorted(item for item,_,_ in bagged))) val, wt = totalvalue(bagged) print("for a total value of %i and a total weight of %i" % (val, -wt))