A-M baby

Task/Knapsack-problem-Unbounded/C/knapsack-problem-unbounded.c

@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct {
+	double val, wgt, vol;
+	const char * name;
+} items[] = { // value in hundreds, volume in thousandths
+	{30, .3, 25,	"panacea"},
+	{18, .2, 15,	"ichor"},
+	{25, 2.,  2,	"gold"},
+	{0,0,0,0}
+};
+
+/* silly setup for silly task */
+int best_cnt[16] = {0}, cnt[16] = {0};
+double best_v = 0;
+
+void grab_em(int idx, double cap_v, double cap_w, double v)
+{
+	double val;
+	int t = cap_w / items[idx].wgt;
+	cnt[idx] = cap_v / items[idx].vol;
+
+	if (cnt[idx] > t) cnt[idx] = t;
+
+	while (cnt[idx] >= 0) {
+		val = v + cnt[idx] * items[idx].val;
+		if (!items[idx + 1].name) {
+			if (val > best_v) {
+				best_v = val;
+				memcpy(best_cnt, cnt, sizeof(int) * (1 + idx));
+			}
+			return;
+		}
+		grab_em(idx + 1, cap_v - cnt[idx] * items[idx].vol,
+			cap_w - cnt[idx] * items[idx].wgt, val);
+		cnt[idx]--;
+	}
+}
+
+int main(void)
+{
+	int i;
+
+	grab_em(0, 250, 25, 0);
+	printf("value: %g hundreds\n", best_v);
+	for (i = 0; items[i].name; i++)
+		printf("%d %s\n", best_cnt[i], items[i].name);
+
+	return 0;
+}