2 files changed, 179 insertions(+), 31 deletions(-)

M main1.c
M main2.c

@@ 2,6 2,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+#define ENTRY_LENGTH 12
+
 FILE *
 openInputFile(void)
 {


@@ 14,36 16,102 @@ openInputFile(void)
 	return fp;
 }
 
+struct list {
+	size_t used;
+	size_t size;
+	int *contents;
+};
+
+int
+createList(struct list *list, size_t initialSize)
+{
+	list->contents = (int *) malloc(initialSize * sizeof(int));
+	if (list->contents == NULL)
+		return 1;
+	list->used = 0;
+	list->size = initialSize;
+	return 0;
+}
+
+int
+insertIntoList(struct list *list, int item)
+{
+	if (list->used == list->size)
+	{
+		list->size *= 2;
+		list->contents = (int *) realloc(list->contents, list->size * sizeof(int));
+		if (list->contents == NULL)
+			return 1;
+	}
+	list->contents[list->used++] = item;
+	return 0;
+}
+
+void
+freeList(struct list *list)
+{
+	free(list->contents);
+}
+
+// Just computes most common value from a set of 1 or 0 because nothing more is
+// needed for this challenge
+int
+mostCommonValue(struct list *list)
+{
+	int numZeros = 0;
+	int numOnes = 0;
+	for (int i = 0; i < list->used; i++)
+	{
+		if (list->contents[i] == 0)
+			numZeros++;
+		else
+			numOnes++;
+	}
+	if (numZeros > numOnes)
+		return 0;
+	else
+		return 1;
+}
+
 int
 main(void)
 {
 	FILE *fp = openInputFile();
 
-	int position = 0;
-	int depth = 0;
+	struct list bits[ENTRY_LENGTH];
+	for (int i = 0; i < ENTRY_LENGTH; i ++)
+		if (createList(&bits[i], 1) != 0)
+			exit(EXIT_FAILURE);
 
 	char *line = NULL;
 	size_t len = 0;
 	ssize_t read;
 	while ((read = getline(&line, &len, fp)) != -1)
 	{
-		char *direction = strtok(line, " ");
-		int magnitude = atoi(strtok(NULL, " "));
+		for (int i = 0; i < ENTRY_LENGTH; i ++)
+			insertIntoList(&bits[i], line[i] - '0');
+	}
 
-		if (strcmp("forward", direction) == 0)
-			position += magnitude;
-		else if (strcmp ("down", direction) == 0)
-			depth += magnitude;
-		else
-			depth -= magnitude;
+	int gamma = 0;
+
+	for (int i = 0; i < ENTRY_LENGTH; i++)
+	{
+		printf("%d: %d\n", i, mostCommonValue(&bits[i]));
+		if (mostCommonValue(&bits[i]))
+			gamma = gamma | (1 << (ENTRY_LENGTH - i - 1)) ;
+		printf("Gamma is: %x\n", gamma);
 	}
 
-	printf("Final position: %d\n", position);
-	printf("Final depth: %d\n", depth);
-	printf("Product: %d\n", position * depth);
+	int epsilon = ~gamma & ((1 << ENTRY_LENGTH) - 1);
+
+	printf("  Gamma %d\n", gamma);
+	printf("Epsilon %d\n", epsilon);
+	printf("Product %d\n", gamma * epsilon);
 
 	fclose(fp);
 	if (line)
 		free(line);
+	for (int i = 0; i < ENTRY_LENGTH; i++)
+		freeList(&bits[i]);
 	exit(EXIT_SUCCESS);
 }

@@ 2,6 2,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+#define ENTRY_LENGTH 12
+
 FILE *
 openInputFile(void)
 {


@@ 14,40 16,118 @@ openInputFile(void)
 	return fp;
 }
 
+struct list {
+	size_t used;
+	size_t size;
+	int *contents;
+};
+
+int
+createList(struct list *list, size_t initialSize)
+{
+	list->contents = (int *) malloc(initialSize * sizeof(int));
+	if (list->contents == NULL)
+		return 1;
+	list->used = 0;
+	list->size = initialSize;
+	return 0;
+}
+
+int
+insertIntoList(struct list *list, int item)
+{
+	if (list->used == list->size)
+	{
+		list->size *= 2;
+		list->contents = (int *) realloc(list->contents, list->size * sizeof(int));
+		if (list->contents == NULL)
+			return 1;
+	}
+	list->contents[list->used++] = item;
+	return 0;
+}
+
+void
+freeList(struct list *list)
+{
+	free(list->contents);
+}
+
+//TODO Make a function that handles deleting an element from the list by index
+
+//TODO Make a function that duplicates a list
+
+// Just computes most common value from a set of 1 or 0 because nothing more is
+// needed for this challenge
+int
+mostCommonValue(struct list *list)
+{
+	int numZeros = 0;
+	int numOnes = 0;
+	for (int i = 0; i < list->used; i++)
+	{
+		if (list->contents[i] == 0)
+			numZeros++;
+		else
+			numOnes++;
+	}
+	if (numZeros > numOnes)
+		return 0;
+	else
+		return 1;
+}
+
 int
 main(void)
 {
 	FILE *fp = openInputFile();
 
-	int position = 0;
-	int depth = 0;
-	int aim = 0;
+	struct list bits[ENTRY_LENGTH];
+	for (int i = 0; i < ENTRY_LENGTH; i ++)
+		if (createList(&bits[i], 1) != 0)
+			exit(EXIT_FAILURE);
+
+	// TODO For Part 2:
+	// Add each _line_ into a list as a list of strings (not ints)
+	// (Duplicate the list for the second calculation)
+	// Iterate over each element, picking the nth bit and add that to a list
+	// of ints
+	// Compute the most common number (1 or 0)
+	// Iterate over each element again and remove the entries which don't
+	// start with the most common number
+	// Repeat until one number remains -> this is the result value
+	// Do the same for the second calculation, but take the least common
+	// number instead of the most common
 
 	char *line = NULL;
 	size_t len = 0;
 	ssize_t read;
 	while ((read = getline(&line, &len, fp)) != -1)
 	{
-		char *direction = strtok(line, " ");
-		int magnitude = atoi(strtok(NULL, " "));
-
-		if (strcmp("forward", direction) == 0)
-		{
-			position += magnitude;
-			depth += aim * magnitude;
-		}
-		else if (strcmp ("down", direction) == 0)
-			aim += magnitude;
-		else
-			aim -= magnitude;
+		for (int i = 0; i < ENTRY_LENGTH; i ++)
+			insertIntoList(&bits[i], line[i] - '0');
 	}
 
-	printf("Final position: %d\n", position);
-	printf("Final depth: %d\n", depth);
-	printf("Product: %d\n", position * depth);
+	int gamma = 0;
+
+	for (int i = 0; i < ENTRY_LENGTH; i++)
+	{
+		printf("%d: %d\n", i, mostCommonValue(&bits[i]));
+		if (mostCommonValue(&bits[i]))
+			gamma = gamma | (1 << (ENTRY_LENGTH - i - 1)) ;
+		printf("Gamma is: %x\n", gamma);
+	}
+
+	int epsilon = ~gamma & ((1 << ENTRY_LENGTH) - 1);
+
+	printf("  Gamma %d\n", gamma);
+	printf("Epsilon %d\n", epsilon);
+	printf("Product %d\n", gamma * epsilon);
 
 	fclose(fp);
 	if (line)
 		free(line);
+	for (int i = 0; i < ENTRY_LENGTH; i++)
+		freeList(&bits[i]);
 	exit(EXIT_SUCCESS);
 }