Finished day 1 in C!

2021/1/.gitignore

@@ -0,0 +1,3 @@
+depth
+depth2
+input

2021/1/Makefile

@@ -0,0 +1,11 @@
+.PHONY := all yeet
+
+all: build run
+
+build:
+	gcc -o depth depth.c
+	gcc -o depth2 depth2.c
+
+run:
+	./depth
+	./depth2

2021/1/depth.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+
+int main() {
+	
+	FILE *input = fopen("input", "r");
+
+	if(input == NULL) {
+		printf("oh noes couldn't open the input file lol\n");
+		return 1;
+	}
+
+
+	char line[255];
+	int count = 0, last_num = INT_MAX;
+	while(fgets(line, sizeof(line), input) != NULL) {
+		int cur_num = atoi(line);
+
+		count += cur_num > last_num;
+		last_num = cur_num;
+	}
+
+	fclose(input);
+
+	printf("There were %d measurements larger than the last.\n", count);
+
+}

2021/1/depth2.c

@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+
+#define WINDOW_SIZE 3
+
+int main() {
+	
+	FILE *input = fopen("input", "r");
+
+	if(input == NULL) {
+		printf("oh noes couldn't open the input file lol\n");
+		return 1;
+	}
+
+
+	char line[255];
+	int index = 0, count = 0, last_num = INT_MAX;
+	int windows[WINDOW_SIZE][WINDOW_SIZE];
+
+	while(fgets(line, sizeof(line), input) != NULL) {
+		int cur_num = atoi(line),
+			cur_index = index % (WINDOW_SIZE);
+
+		// Put values diagonal into the 3x3 grid, like this
+		// A B C
+		// B C A
+		// C A B
+		for(int i=0; i<WINDOW_SIZE; i++){
+			int cur_col = (cur_index + i) % WINDOW_SIZE;
+			windows[i][cur_col] = cur_num;
+		}
+
+		index++;
+		if(index < WINDOW_SIZE) // skip first 3 values
+			continue;
+
+		// Calculate average for current column, e.g.
+		// A B C
+		// B C A
+		// C A B
+		// ^
+		int sum = 0;
+		for(int i=0; i<WINDOW_SIZE; i++)
+			sum += windows[cur_index][i];
+		
+		count += sum > last_num;
+		last_num = sum;
+	}
+
+	fclose(input);
+
+	printf("There were %d measurements larger than the last.\n", count);
+
+}

README.md

@@ -2,6 +2,9 @@
 
 Heya! This is my advent of code repo (as you might have guessed). In here you'll find my solutions of the advent of code exercises.
 
+# 2021
+
+So similar to last year, a different language each day. Different though: I pick the language myself instead of using the little seeded ransomizer. Hopefully this helps with me finishing it when I am busy that day (by picking a language I already know).
 
 ## 2020