RosettaCodeData/Task/Knapsack-problem-0-1/C/knapsack-problem-0-1.c

79 lines
2.3 KiB
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;
}