advent-of-code

commit 9149ffedaf4231a9431cf7102332093c3c5dfb04
parent b1019419e368d387c5182c277c4e8710b035e446
Author: Jake Bauer <jbauer@paritybit.ca>
Date:   Thu, 16 Dec 2021 15:08:44 -0500

Complete Day 2 challenges

Diffstat:
M
main1.c
 | 
35
+++++++++++++++++++----------------
M
main2.c
 | 
53
+++++++++++++++++++----------------------------------

2 files changed, 38 insertions(+), 50 deletions(-)
diff --git a/main1.c b/main1.c
@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 FILE *
 openInputFile(void)
@@ -16,31 +17,33 @@ openInputFile(void)
 int
 main(void)
 {
+	FILE *fp = openInputFile();
+
+	int position = 0;
+	int depth = 0;
+
 	char *line = NULL;
-	int increases = 0;
-	int currentValue = 0;
-	int previousValue = -1;
 	size_t len = 0;
 	ssize_t read;
-
-	FILE *fp = openInputFile();
-
 	while ((read = getline(&line, &len, fp)) != -1)
 	{
-		if (previousValue < 0)
-			previousValue = atoi(line);
-
-		currentValue = atoi(line);
-
-		if (currentValue > previousValue)
-			increases++;
-
-		previousValue = currentValue;
+		char *direction = strtok(line, " ");
+		int magnitude = atoi(strtok(NULL, " "));
+
+		if (strcmp("forward", direction) == 0)
+			position += magnitude;
+		else if (strcmp ("down", direction) == 0)
+			depth += magnitude;
+		else
+			depth -= magnitude;
 	}
 
+	printf("Final position: %d\n", position);
+	printf("Final depth: %d\n", depth);
+	printf("Product: %d\n", position * depth);
+
 	fclose(fp);
 	if (line)
 		free(line);
-	printf("%d\n", increases);
 	exit(EXIT_SUCCESS);
 }
diff --git a/main2.c b/main2.c
@@ -1,7 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
-
-#define ARR_SIZE 3
+#include <string.h>
 
 FILE *
 openInputFile(void)
@@ -16,53 +15,39 @@ openInputFile(void)
 }
 
 int
-sumArray(int *array, int size)
-{
-	int sum = 0;
-	for (int i = 0; i < size; i++)
-		sum += array[i];
-	return sum;
-}
-
-int
 main(void)
 {
 	FILE *fp = openInputFile();
-	int increases = 0;
 
-	int array[ARR_SIZE] = { 0 };
-	int arrayPosition = 0;
-	int currentSum = 0;
-	int previousSum = 0;
-	int firstFill = 1;
+	int position = 0;
+	int depth = 0;
+	int aim = 0;
 
 	char *line = NULL;
 	size_t len = 0;
 	ssize_t read;
 	while ((read = getline(&line, &len, fp)) != -1)
 	{
-		if (arrayPosition == ARR_SIZE) {
-			if (firstFill)
-				previousSum = currentSum;
-			firstFill = 0;
-			arrayPosition = 0;
-		}
-
-		currentSum = sumArray(array, ARR_SIZE);
-		array[arrayPosition++] = atoi(line);
-
-		// Don't do comparisons until we've filled the array
-		if (firstFill)
-			continue;
+		char *direction = strtok(line, " ");
+		int magnitude = atoi(strtok(NULL, " "));
 
-		if (currentSum > previousSum)
-			increases++;
-		previousSum = currentSum;
+		if (strcmp("forward", direction) == 0)
+		{
+			position += magnitude;
+			depth += aim * magnitude;
+		}
+		else if (strcmp ("down", direction) == 0)
+			aim += magnitude;
+		else
+			aim -= magnitude;
 	}
 
+	printf("Final position: %d\n", position);
+	printf("Final depth: %d\n", depth);
+	printf("Product: %d\n", position * depth);
+
 	fclose(fp);
 	if (line)
 		free(line);
-	printf("%d\n", increases);
 	exit(EXIT_SUCCESS);
 }