1 files changed, 79 insertions, 0 deletions
diff --git a/03.c b/03.c
new file mode 100644
index 0000000..d5b10fd
--- /dev/null
+++ b/03.c
@@ -0,0 +1,79 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <err.h>
+#include <string.h>
+#include "input.h"
+
+#define INPUT "input/03.txt"
+#define EXPECTED1 7446L
+#define EXPECTED2 2646L
+
+void part1(struct input_str* input) {
+	long priority_sum = 0;
+	char duplicate_item;
+	for(size_t i = 0; i < input->line_count; i++) {
+		int rucksack_size = strlen(input->lines[i]);
+		int compartment_size = rucksack_size / 2;
+		for(int j = 0; j < compartment_size; j++) {
+			for(int k = compartment_size; k <= rucksack_size; k++) {
+				if(input->lines[i][j] == input->lines[i][k]) {
+					duplicate_item = input->lines[i][j];
+					goto found_duplicate;
+				}
+			}
+		}
+		err(2, "rucksack %ld: no duplicate found", i);
+
+found_duplicate:
+	if(duplicate_item > 'a')
+		priority_sum += duplicate_item - 'a' + 1;
+	else
+		priority_sum += duplicate_item - 'A' + 27;
+	}
+
+	CHECK(priority_sum, EXPECTED1)
+}
+
+void part2(struct input_str* input) {
+	long priority_sum = 0;
+	char badge;
+	// loop on groups of elves
+	for(size_t i = 0; i < input->line_count; i += 3) {
+		// loop on first rucksack content
+		for(size_t j = 0; j <= strlen(input->lines[i]); j++) {
+			// second rucksack
+			for(size_t k = 0; k <= strlen(input->lines[i+1]); k++) {
+				// third rucksack
+				for(size_t l = 0; l <= strlen(input->lines[i+2]); l++) {
+					if(input->lines[i][j] == input->lines[i+1][k] && input->lines[i][j] == input->lines[i+2][l]) {
+						badge = input->lines[i][j];
+						goto found_bagde;
+					}
+				}
+			}
+		}
+		err(2, "rucksack %ld: no badge found", i);
+
+found_bagde:
+	if(badge > 'a')
+		priority_sum += badge - 'a' + 1;
+	else
+		priority_sum += badge - 'A' + 27;
+	}
+
+	CHECK(priority_sum, EXPECTED2)
+}
+
+int main() {
+	// read input
+	struct input_str input;
+	input_str_read(&input, INPUT);
+
+	// do stuff
+	part1(&input);
+	part2(&input);
+
+	// cleanup & exit
+	input_str_free(&input);
+	return 0;
+}