X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=06a.c;h=e2634d21ba73e026ecccfd2f7be314b99e793a36;hb=967152a3319e0207e16901ecc0344edaf8c8193e;hp=92a1b8ae972e27c0efd07b91e2adaef3c4472633;hpb=46b95a2f1d484eed878202f204561932dd9c548b;p=advent21.git

diff --git a/06a.c b/06a.c
index 92a1b8a..e2634d2 100644
--- a/06a.c
+++ b/06a.c
@@ -4,31 +4,20 @@
 
 int main()
 {
-	char buf[1000];
-	if (fgets(buf, 1000, stdin) == NULL)
-		return 1;
-	long fish0[9] = {0};
-	long fish1[9] = {0};
-	long *this = &fish0[0];
-	long *that = &fish1[0];
+	char *buf = NULL;
+	size_t len = 0;
+	long fish[9] = {0};
 
+	getline(&buf, &len, stdin);
 	char *p = strtok(buf, ",");
-	this[atoi(p)]++;
+	fish[atoi(p)]++;
 	while ((p = strtok(NULL, ",")) != NULL)
-		this[atoi(p)]++;
+		fish[atoi(p)]++;
 
-	for (long day = 0; day<80; day++) {
-		that[8] = this[0];
-		for (long i = 0; i<8; i++)
-			that[i] = this[i+1];
-		that[6] += this[0];
-		long *tmp = this;
-		this = that;
-		that = tmp;
-	}
+	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 += this[i];
-	printf("%lu\n", sum);
+	for (long i = 1; i<=8; i++)
+		fish[0] += fish[i];
+	printf("%ld\n", fish[0]);
 }