From: Mart Lubbers <mart@martlubbers.net>
Date: Mon, 6 Dec 2021 09:22:05 +0000 (+0100)
Subject: use getline, experiment with gmp
X-Git-Url: https://git.martlubbers.net/?a=commitdiff_plain;h=7ba426df9118b57ac5cc95085f89c91477a9a59f;p=advent21.git

use getline, experiment with gmp
---

diff --git a/06a.c b/06a.c
index c9152c6..e2634d2 100644
--- a/06a.c
+++ b/06a.c
@@ -4,10 +4,11 @@
 
 int main()
 {
-	char buf[1000];
-	if (fgets(buf, 1000, stdin) == NULL)
-		return 1;
+	char *buf = NULL;
+	size_t len = 0;
 	long fish[9] = {0};
+
+	getline(&buf, &len, stdin);
 	char *p = strtok(buf, ",");
 	fish[atoi(p)]++;
 	while ((p = strtok(NULL, ",")) != NULL)
@@ -16,8 +17,7 @@ int main()
 	for (long day = 0; day<80; day++)
 		fish[(day+7) % 9] += fish[day%9];
 
-	long sum = 0;
-	for (long i = 0; i<=8; i++)
-		sum += fish[i];
-	printf("%lu\n", sum);
+	for (long i = 1; i<=8; i++)
+		fish[0] += fish[i];
+	printf("%ld\n", fish[0]);
 }
diff --git a/06b.c b/06b.c
index 0b2f076..bd2e220 100644
--- a/06b.c
+++ b/06b.c
@@ -2,22 +2,32 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <gmp.h>
+
 int main()
 {
-	char buf[1000];
-	if (fgets(buf, 1000, stdin) == NULL)
-		return 1;
-	long fish[9] = {0};
+	char *buf = NULL;
+	size_t len = 0;
+	mpz_t fish[9];
+	for (int i = 0; i<9; i++)
+		mpz_init_set_ui(fish[i], 0);
+
+	getline(&buf, &len, stdin);
 	char *p = strtok(buf, ",");
-	fish[atoi(p)]++;
-	while ((p = strtok(NULL, ",")) != NULL)
-		fish[atoi(p)]++;
+	int n = atoi(p);
+	mpz_add_ui(fish[n], fish[n], 1);
+	while ((p = strtok(NULL, ",")) != NULL) {
+		n = atoi(p);
+		mpz_add_ui(fish[n], fish[n], 1);
+	}
 
-	for (long day = 0; day<256; day++)
-		fish[(day+7) % 9] += fish[day%9];
+	for (long day = 0; day<256; day++) {
+		n = (day+7) % 9;
+		mpz_add(fish[n], fish[n], fish[day%9]);
+	}
 
-	long sum = 0;
-	for (long i = 0; i<=8; i++)
-		sum += fish[i];
-	printf("%lu\n", sum);
+	for (long i = 1; i<=8; i++)
+		mpz_add(fish[0], fish[0], fish[i]);
+	mpz_out_str(stdout, 10, fish[0]);
+	putchar('\n');
 }