Task: Knapsack problem_0-1

C: #include <stdio.h>
#include <stdlib.h>

typedef struct {
    char *name;
    int weight;
    int value;
} item_t;

item_t 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},
};

int *knapsack (item_t *items, int n, int w) {
    int i, j, a, b, *mm, **m, *s;
    mm = calloc((n + 1) * (w + 1), sizeof (int));
    m = malloc((n + 1) * sizeof (int *));
    m[0] = mm;
    for (i = 1; i <= n; i++) {
        m[i] = &mm[i * (w + 1)];
        for (j = 0; j <= w; j++) {
            if (items[i - 1].weight > j) {
                m[i][j] = m[i - 1][j];
            }
            else {
                a = m[i - 1][j];
                b = m[i - 1][j - items[i - 1].weight] + items[i - 1].value;
                m[i][j] = a > b ? a : b;
            }
        }
    }
    s = calloc(n, sizeof (int));
    for (i = n, j = w; i > 0; i--) {
        if (m[i][j] > m[i - 1][j]) {
            s[i - 1] = 1;
            j -= items[i - 1].weight;
        }
    }
    free(mm);
    free(m);
    return s;
}

int main () {
    int i, n, tw = 0, tv = 0, *s;
    n = sizeof (items) / sizeof (item_t);
    s = knapsack(items, n, 400);
    for (i = 0; i < n; i++) {
        if (s[i]) {
            printf("%-22s %5d %5d\n", items[i].name, items[i].weight, items[i].value);
            tw += items[i].weight;
            tv += items[i].value;
        }
    }
    printf("%-22s %5d %5d\n", "totals:", tw, tv);
    return 0;
}







Python: from itertools import combinations

def anycomb(items):
    ' return combinations of any length from the items '
    return ( comb
             for r in range(1, len(items)+1)
             for comb in combinations(items, r)
             )

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),
    )
bagged = max( anycomb(items), key=totalvalue) 
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))