Day 6

day6/Makefile

@@ -0,0 +1,10 @@
+solution-part%: solution-part%.c
+	gcc $< -o $@
+
+test-%: solution-% example.txt
+	$< example.txt
+
+run-%: solution-% realinput.txt
+	$< realinput.txt
+
+.PHONY: $(patsubst %,run-%, 1 2) $(patsubst %,test-%, 1 2)

day6/example.txt

@@ -0,0 +1 @@
+3,4,3,1,2

day6/realinput.txt

@@ -0,0 +1 @@
+4,1,1,4,1,1,1,1,1,1,1,1,3,4,1,1,1,3,1,3,1,1,1,1,1,1,1,1,1,3,1,3,1,1,1,5,1,2,1,1,5,3,4,2,1,1,4,1,1,5,1,1,5,5,1,1,5,2,1,4,1,2,1,4,5,4,1,1,1,1,3,1,1,1,4,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,5,1,1,2,1,1,1,1,1,1,1,2,4,4,1,1,3,1,3,2,4,3,1,1,1,1,1,2,1,1,1,1,2,5,1,1,1,1,2,1,1,1,1,1,1,1,2,1,1,4,1,5,1,3,1,1,1,1,1,5,1,1,1,3,1,2,1,2,1,3,4,5,1,1,1,1,1,1,5,1,1,1,1,1,1,1,1,3,1,1,3,1,1,4,1,1,1,1,1,2,1,1,1,1,3,2,1,1,1,4,2,1,1,1,4,1,1,2,3,1,4,1,5,1,1,1,2,1,5,3,3,3,1,5,3,1,1,1,1,1,1,1,1,4,5,3,1,1,5,1,1,1,4,1,1,5,1,2,3,4,2,1,5,2,1,2,5,1,1,1,1,4,1,2,1,1,1,2,5,1,1,5,1,1,1,3,2,4,1,3,1,1,2,1,5,1,3,4,4,2,2,1,1,1,1,5,1,5,2

day6/solution-part1.c

@@ -0,0 +1,103 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdlib.h>
+
+
+typedef struct LanternFishListItem LanternFishListItem;
+struct LanternFishListItem {
+	unsigned int daysToSpawn;
+	LanternFishListItem *next;
+};
+
+void printFrom( LanternFishListItem *first ){
+	printf("%i,", first->daysToSpawn);
+	if ( first->next != NULL ) printFrom(first->next);
+}
+
+unsigned int countFrom( LanternFishListItem *current ){
+	unsigned int count = 1;
+	while ( current->next != NULL ){
+		count++;
+		current = current->next;
+	}
+	return count;
+}
+
+int main( int argc, char *argv[] ){
+	if( argc == 2 ) {
+
+
+		FILE *fp=fopen(argv[1], "r");
+
+		LanternFishListItem *first = NULL;
+		LanternFishListItem *previous = NULL;
+		unsigned int no;
+		char ch;
+		while ( fscanf( fp, "%i%c", &no, &ch ) ){
+
+			LanternFishListItem *lf = (LanternFishListItem*)malloc(sizeof(LanternFishListItem));
+			lf->next = NULL;
+			lf->daysToSpawn = no;
+
+			if ( first == NULL ){
+				first = lf;
+			} else {
+				previous->next = lf;
+			}
+
+			previous = lf;
+
+			if ( ch == '\n' ) break;
+		}
+
+		for ( unsigned int i = 0; i < 80; i++ ){
+			unsigned int toAdd=0;
+			LanternFishListItem *current = first;
+			while (current != NULL){
+				if ( current->daysToSpawn == 0 ){
+					toAdd++;
+					current->daysToSpawn = 7;
+				}
+				current->daysToSpawn--;
+				if ( current->next != NULL )
+					current = current->next;
+				else
+					break;
+
+			}
+
+
+			previous = current;
+			//printf("On day %i add %i fish\n", i, toAdd);
+			for (unsigned int j = 0; j < toAdd; j++){
+				LanternFishListItem *lf = (LanternFishListItem*)malloc(sizeof(LanternFishListItem));
+				lf->next = NULL;
+				lf->daysToSpawn = 8;
+				previous->next = lf;
+				previous = lf;
+			}
+
+			//printf("After %3i day: ", i+1);
+			//printFrom(first);
+			//printf("\n");
+
+
+
+
+
+
+		}
+		printf("There are %i Fish.\n",countFrom(first));
+
+
+		fclose(fp);
+
+
+
+		return 0;
+	} else {
+		printf("You need to provide a file\n");
+		return 1;
+	}
+}

day6/solution-part2.c

@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define POSSIBLE_SPAWN_AGES 9
+
+unsigned long countFish(unsigned long *fishCount){
+	unsigned long count = 0;
+	for( unsigned int i = 0; i < POSSIBLE_SPAWN_AGES; i++ ){
+		count += fishCount[i];
+	}
+	return count;
+}
+
+int main( int argc, char *argv[] ){
+	if( argc == 2 ) {
+
+
+		FILE *fp=fopen(argv[1], "r");
+
+		unsigned int no;
+		char ch;
+		// I realised that the ordering of the fish doesn't matter. What matters is how many of them are of each age.
+		// This array will contain the number of fish of age 1 in fishCount[1] and so on.
+		unsigned long fishCount[POSSIBLE_SPAWN_AGES] = {0};
+		while ( fscanf( fp, "%i%c", &no, &ch ) ){
+			fishCount[no]++;
+			if ( ch == '\n' ) break;
+		}
+
+		for ( unsigned int i = 0; i < 256; i++ ){
+			// "backup" the number of fish of age 0 as the memmove will loose this
+			unsigned long age0 = fishCount[0];
+			memmove( &fishCount[0], &fishCount[1], sizeof(unsigned long) * (POSSIBLE_SPAWN_AGES - 1) );
+
+			// All the fish that had a spawn_age of 0 will now have a spawn age of 6
+			fishCount[6] += age0;
+
+			// They will also all have a new fish with age of 8
+			fishCount[8] = age0;
+
+			//printf("\nDay %i:\n", i+1);
+			//for( unsigned int j = 0; j < POSSIBLE_SPAWN_AGES; j++){
+			//	printf("Fish with spawn age %i: %lu\n", j, fishCount[j]);
+			//}
+		}
+		printf("There are %lu Fish.\n",countFish(fishCount));
+
+
+		fclose(fp);
+
+
+
+		return 0;
+	} else {
+		printf("You need to provide a file\n");
+		return 1;
+	}
+}