First attempt at puzzle 11 part 2 (buggy)

Turned item worry levels to unsigned long in an attempt to not overflow.

Added checks for overflow, and they get hit - quickly - without the
calming factor. Will need to think about this. (or try bignums)

1 files changed, 64 insertions, 13 deletions

diff --git a/11.c b/11.c
index ec06772..5f14466 100644
--- a/11.c
+++ b/11.c
@@ -1,8 +1,10 @@
 
 #include <ctype.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 
 enum worry_op {
@@ -14,7 +16,7 @@ enum worry_op {
 
 
 struct monkey {
-	int * items;
+	unsigned long * items;
 	int nitems;
 	enum worry_op wo;
 	int wparam;
@@ -62,7 +64,7 @@ monkey_additem(struct monkey * m, int worry)
 	void * p;
 
 	++m->nitems;
-	p = realloc(m->items, m->nitems * sizeof(int));
+	p = realloc(m->items, m->nitems * sizeof(unsigned long));
 	if (!p)
 		return 0;
 	m->items = p;
@@ -74,24 +76,54 @@ monkey_additem(struct monkey * m, int worry)
 void
 monkey_dump(struct monkey const * m, int n)
 {
-	int * i;
+	unsigned long * item;
 
 	fprintf(stderr, "Monkey %d: %d/%d/%d/%d/%d/%d: ",
 			n, m->wo, m->wparam, m->test_div, m->test_true, m->test_false, m->inspections);
-	for (i = m->items; i < m->items + m->nitems; ++i) {
-		fprintf(stderr, "%s%d", i == m->items ? "" : ", ", *i);
+	for (item = m->items; item < m->items + m->nitems; ++item) {
+		fprintf(stderr, "%s%lu", item == m->items ? "" : ", ", *item);
 	}
 	fprintf(stderr, "\n");
 }
 
 
 int
-main()
+main(int argc, char ** argv)
 {
 	char buf[BUFSIZ];
 	struct monkey * monkeys = NULL, * m = NULL;
 	int nmonkeys = 0;
 	int i, j;
+	int calming = 3, rounds = 20;
+
+	while ((i = getopt(argc, argv, "p:c:r:")) != -1) {
+		switch (i) {
+		case 'p':
+			switch (atol(optarg)) {
+			case 1: calming = 3; rounds = 20; break;
+			case 2: calming = 1; rounds = 10000; break;
+			default:
+				fprintf(stderr, "Unexpected part %d\n", atoi(optarg));
+				return -1;
+			}
+			break;
+
+		case 'c':
+			calming = atoi(optarg);
+			if (calming == 0) {
+				fprintf(stderr, "Unexpected calming factor %d\n", calming);
+				return -1;
+			}
+			break;
+
+		case 'r':
+			rounds = atoi(optarg);
+			break;
+
+		default:
+			return -1;
+		}
+	}
 
 	// Read monkey data
 	while (fgets(buf, sizeof(buf), stdin)) {
@@ -176,20 +208,39 @@ main()
 	}
 
 	// Perform monkey inspection rounds
-	for (i = 0; i < 20; ++i) {
+	for (i = 0; i < rounds; ++i) {
 		for (m = monkeys; m < monkeys + nmonkeys; ++m) {
-			int * item;
+			unsigned long * item;
 
 			for (item = m->items; item < m->items + m->nitems; ++item) {
 				int catcher;
 
 				switch (m->wo) {
-				case WO_NONE: break; /* shouldn't happen */
-				case WO_ADD: *item += m->wparam; break;
-				case WO_MUL: *item *= m->wparam; break;
-				case WO_SQR: *item *= *item; break;
+				case WO_NONE:
+					break; /* shouldn't happen */
+				case WO_ADD:
+					if (*item > ULONG_MAX - m->wparam)
+						fprintf(stderr, "%d/%d/%d: Overflow: %lu > %lu - %d\n",
+								i, (int) (monkeys - m), (int) (item - m->items),
+								*item, ULONG_MAX, m->wparam);
+					*item += m->wparam;
+					break;
+				case WO_MUL:
+					if (*item >= ULONG_MAX / m->wparam)
+						fprintf(stderr, "%d/%d/%d: Overflow: %lu >= %lu / %d\n",
+								i, (int) (monkeys - m), (int) (item - m->items),
+								*item, ULONG_MAX, m->wparam);
+					*item *= m->wparam;
+					break;
+				case WO_SQR:
+					if (*item >= ULONG_MAX / *item)
+						fprintf(stderr, "%d/%d/%d: Overflow: %lu >= %lu / %lu\n",
+								i, (int) (monkeys - m), (int) (item - m->items),
+								*item, ULONG_MAX, *item);
+					*item *= *item;
+					break;
 				}
-				*item /= 3;
+				*item /= calming;
 
 				catcher = *item % m->test_div ? m->test_false : m->test_true;
 				monkey_additem(monkeys + catcher, *item);