A-M baby

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

@@ -0,0 +1,77 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+typedef struct {
+        const char * name;
+        int weight, value;
+} item_t;
+
+item_t item[] = {
+        {"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},
+        {"suntancream",             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}
+};
+
+#define n_items (sizeof(item)/sizeof(item_t))
+
+typedef struct {
+        uint32_t bits; /* 32 bits, can solve up to 32 items */
+        int value;
+} solution;
+
+
+void optimal(int weight, int idx, solution *s)
+{
+        solution v1, v2;
+        if (idx < 0) {
+                s->bits = s->value = 0;
+                return;
+        }
+
+        if (weight < item[idx].weight)
+                return optimal(weight, idx - 1, s);
+
+        optimal(weight, idx - 1, &v1);
+        optimal(weight - item[idx].weight, idx - 1, &v2);
+
+        v2.value += item[idx].value;
+        v2.bits |= (1 << idx);
+
+        *s = (v1.value >= v2.value) ? v1 : v2;
+}
+
+int main()
+{
+        int i = 0, w = 0;
+        solution s = {0, 0};
+        optimal(400, n_items - 1, &s);
+
+        for (i = 0; i < n_items; i++) {
+                if (s.bits & (1 << i)) {
+                        printf("%s\n", item[i].name);
+                        w += item[i].weight;
+                }
+        }
+        printf("Total value: %d; weight: %d\n", s.value, w);
+        return 0;
+}