advent2021

commit 53faf8ede208ca33cafabf4346559b2eac484744
parent cf69ab1ab4a79faea843cc69927e55a00953f11e
Author: bsandro <[email protected]>
Date:   Wed,  1 Dec 2021 22:00:15 +0200

Day 01, puzzle 2

Diffstat:
M
day01/main.c
 | 
39
++++++++++++---------------------------
A
day01/puzzle1.c
 | 
33
+++++++++++++++++++++++++++++++++
A
day01/puzzle1.h
 | 
1
+
A
day01/puzzle2.c
 | 
56
++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
day01/puzzle2.h
 | 
1
+

5 files changed, 103 insertions(+), 27 deletions(-)
diff --git a/day01/main.c b/day01/main.c
@@ -1,39 +1,24 @@
 #include <stdio.h>
-#include <stdlib.h>
-#include <errno.h>
-#include <string.h>
+#include "puzzle1.h"
+#include "puzzle2.h"
 
 int main(int argc, char *argv[]) {
-	printf("advent of code day 01\n");
-	if (argc <= 1) {
-		printf("Usage: %s inputfile.txt\n", argv[0]);
-		return 0;
-	}
+	printf("Advent of Code: day 01\n");
 
-	FILE *infile = fopen(argv[1], "r");
-	if (infile == NULL) {
-		printf("fopen() error: %s\n", strerror(errno));
+	if (argc <= 0) {
 		return -1;
 	}
-
-	char *buf = NULL;
-	size_t len = 0;
-	int prev_depth = -1;
-	int counter = 0;
-	while ((buf = fgetln(infile, &len)) != NULL) {
-		if (len == 0) {
-			break;
-		}
-		int depth = atoi(buf);
-		if (prev_depth > -1 && depth > prev_depth) {
-			++counter;
-		}
-		prev_depth = depth;
+	if (argc <= 1) {
+		printf("Usage: %s inputfile.txt\n", argv[0]);
+		return -1;
 	}
 
-	printf("1: %d\n", counter);
+	const char *filename = argv[1];
 
-	fclose(infile);
+	int counter1 = puzzle1(filename);
+	printf("Puzzle #1: %d\n", counter1);
+	int counter2 = puzzle2(filename);
+	printf("Puzzle #2: %d\n", counter2);
 
 	return 0;
 }
diff --git a/day01/puzzle1.c b/day01/puzzle1.c
@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+
+int puzzle1(const char *filename) {
+	FILE *infile = fopen(filename, "r");
+	if (infile == NULL) {
+		fprintf(stderr, "fopen() error: %s\n", strerror(errno));
+		return -1;
+	}
+
+	char *buf = NULL;
+	size_t len = 0;
+	int prev_depth = -1;
+	int counter = 0;
+
+	while ((buf = fgetln(infile, &len)) != NULL) {
+		if (len == 0) {
+			fprintf(stderr, "Error: invalid input line\n");
+			counter = -1;
+			break;
+		}
+		int depth = atoi(buf);
+		if (prev_depth > -1 && depth > prev_depth) {
+			++counter;
+		}
+		prev_depth = depth;
+	}
+
+	fclose(infile);
+	return counter;
+}
diff --git a/day01/puzzle1.h b/day01/puzzle1.h
@@ -0,0 +1 @@
+int puzzle1(const char *filename);
diff --git a/day01/puzzle2.c b/day01/puzzle2.c
@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <stdbool.h>
+
+void rotate_window(int window[3]) {
+	int tmp = window[0];
+	window[0] = window[1];
+	window[1] = window[2];
+	window[2] = tmp;
+}
+
+int sum_window(int window[3]) {
+	return window[0] + window[1] + window[2];
+}
+
+int sum_new_window(int window[3], int value) {
+	return window[1] + window[2] + value;
+}
+
+bool is_window_full(int window[3]) {
+	return window[0] > 0 && window[1] > 0 && window[2] > 0;
+}
+
+int puzzle2(const char *filename) {
+	FILE *infile = fopen(filename, "r");
+	if (infile == NULL) {
+		fprintf(stderr, "fopen() error: %s\n", strerror(errno));
+		return -1;
+	}
+
+	char *buf = NULL;
+	size_t len = 0;
+	int window[3] = {0, 0, 0};
+	int counter = 0;
+
+	while ((buf = fgetln(infile, &len)) != NULL) {
+		if (len == 0) {
+			fprintf(stderr, "Error: invalid input line\n");
+			counter = -1;
+			break;
+		}
+		int depth = atoi(buf);
+		int sum_win = sum_window(window);
+		int sum_new = sum_new_window(window, depth);
+		if (is_window_full(window) && sum_win > 0 && sum_new > sum_win) {
+			++counter;
+		}
+		rotate_window(window);
+		window[2] = depth;
+	}
+
+	fclose(infile);
+	return counter;
+}
diff --git a/day01/puzzle2.h b/day01/puzzle2.h
@@ -0,0 +1 @@
+int puzzle2(const char *filename);