From 736823f313bd2e00e49a1b52aaf0ea68a79db438 Mon Sep 17 00:00:00 2001
From: Vincent Douillet <vincent@vdouillet.fr>
Date: Fri, 3 Dec 2021 17:01:37 +0100
Subject: improve input handling & merge part 1 and 2 for the first days

---
 02.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 02.c

(limited to '02.c')

diff --git a/02.c b/02.c
new file mode 100644
index 0000000..30af77f
--- /dev/null
+++ b/02.c
@@ -0,0 +1,88 @@
+#include <stdio.h>
+#include <err.h>
+#include <string.h>
+#include "input.h"
+
+#define INPUT "input/02.txt"
+
+enum direction { forward, up, down };
+
+struct submarine_move {
+	enum direction dir;
+	int length;
+};
+
+void parse_move(char* string, struct submarine_move* move) {
+	if(*string == 'f')
+		move->dir = forward;
+	else if(*string == 'u')
+		move->dir = up;
+	else if(*string == 'd')
+		move->dir = down;
+	else
+		err(1, "direction inconnue %c", *string);
+
+	size_t stringLength = strlen(string);
+	char digit = string[stringLength - 2];
+	if(digit < '0' || digit > '9')
+		err(1, "longueur inconnue %c", digit);
+	move->length = digit - '0';
+}
+
+void part1(struct input_str* input) {
+	struct submarine_move currentMove;
+	long forwardDst = 0;
+	long downDst = 0;
+	for(size_t i = 0; i < input->line_count; i++) {
+		parse_move(input->lines[i], &currentMove);
+		switch(currentMove.dir) {
+			case forward:
+				forwardDst += currentMove.length;
+				continue;
+			case up:
+				downDst -= currentMove.length;
+				continue;
+			case down:
+				downDst += currentMove.length;
+				continue;
+		}
+	}
+	printf("%ld\n", forwardDst * downDst);
+}
+
+void part2(struct input_str* input) {
+	struct submarine_move currentMove;
+	long forwardDst = 0;
+	long downDst = 0;
+	long aim = 0;
+	for(size_t i = 0; i < input->line_count; i++) {
+		parse_move(input->lines[i], &currentMove);
+		switch(currentMove.dir) {
+			case forward:
+				forwardDst += currentMove.length;
+				downDst += currentMove.length * aim;
+				continue;
+			case up:
+				aim -= currentMove.length;
+				continue;
+			case down:
+				aim += currentMove.length;
+				continue;
+		}
+	}
+	printf("%ld\n", forwardDst * downDst);
+}
+
+int main() {
+	// read input data
+	struct input_str input;
+	input_str_read(&input, INPUT);
+
+	// do stuff
+	part1(&input);
+	part2(&input);
+
+	// cleanup & exit
+	input_str_free(&input);
+	return 0;
+}
-- 
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