solve day 5

aoc.h

@@ -3,7 +3,7 @@
 
 #include <stdbool.h>
 
-typedef int (*solution_cb)(void*);
+typedef void (*solution_cb)(void*);
 typedef void* (*parse_cb)(char** lines, int count);
 typedef struct {
 	int day;

day1.c

@@ -46,7 +46,7 @@ static void *day1_parse(char **lines, int line_count)
 	return data;
 }
 
-static int day1_part1(void *p)
+static void day1_part1(void *p)
 {
 	Data *data = (Data*)p;
 	int max_calories = 0;
@@ -57,10 +57,10 @@ static int day1_part1(void *p)
 		}
 		max_calories = MAX(max_calories, calories);
 	}
-	return max_calories;
+	printf("%d\n", max_calories);
 }
 
-static int day1_part2(void *p)
+static void day1_part2(void *p)
 {
 	Data *data = (Data*)p;
 	int max_calories1 = 0;
@@ -82,7 +82,7 @@ static int day1_part2(void *p)
 			max_calories3 = calories;
 		}
 	}
-	return max_calories1 + max_calories2 + max_calories3;
+	printf("%d\n", max_calories1 + max_calories2 + max_calories3);
 }
 
 ADD_SOLUTION(1, day1_parse, day1_part1, day1_part2);

day2.c

@@ -22,7 +22,7 @@ static void *day2_parse(char **lines, int line_count)
 	return vec;
 }
 
-static int day2_part1(void *p)
+static void day2_part1(void *p)
 {
 	Vec *rounds = p;
 	int result = 0;
@@ -49,10 +49,10 @@ static int day2_part1(void *p)
 			result += 6;
 		}
 	}
-	return result;
+	printf("%d\n", result);
 }
 
-static int day2_part2(void *p)
+static void day2_part2(void *p)
 {
 	Vec *data = p;
 	int result = 0;
@@ -81,7 +81,7 @@ static int day2_part2(void *p)
 			result += 6;
 		}
 	}
-	return result;
+	printf("%d\n", result);
 }
 
 ADD_SOLUTION(2, day2_parse, day2_part1, day2_part2);

day3.c

@@ -45,7 +45,7 @@ static int get_priority(char c)
 		return 0;
 }
 
-static int day3_part1(void *p)
+static void day3_part1(void *p)
 {
 	Vec *vec = p;
 	int result = 0;
@@ -59,10 +59,10 @@ static int day3_part1(void *p)
 			fprintf(stderr, "Unknown common char at line: %zu\n", i+1);
 		}
 	}
-	return result;
+	printf("%d\n", result);
 }
 
-static int day3_part2(void *p)
+static void day3_part2(void *p)
 {
 	Vec *vec = p;
 	int result = 0;
@@ -88,7 +88,7 @@ static int day3_part2(void *p)
 			fprintf(stderr, "Unknown common char at line: %zu-%zu\n", i+1, i+3);
 		}
 	}
-	return result;
+	printf("%d\n", result);
 }
 
 ADD_SOLUTION(3, day3_parse, day3_part1, day3_part2);

day4.c

@@ -41,7 +41,7 @@ static void *day4_parse(char **lines, int line_count)
 	return vec;
 }
 
-static int day4_part1(void *p)
+static void day4_part1(void *p)
 {
 	Vec *vec = p;
 	int result = 0;
@@ -54,10 +54,10 @@ static int day4_part1(void *p)
 			result++;
 		}
 	}
-	return result;
+	printf("%d\n", result);
 }
 
-static int day4_part2(void *p)
+static void day4_part2(void *p)
 {
 	Vec *vec = p;
 	int result = 0;
@@ -71,7 +71,7 @@ static int day4_part2(void *p)
 			result++;
 		}
 	}
-	return result;
+	printf("%d\n", result);
 }
 
 

day5.c

@@ -0,0 +1,165 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/param.h>
+
+#include "aoc.h"
+#include "vec.h"
+
+typedef struct {
+	int from, to, amount;
+} Move;
+
+typedef struct {
+	Vec *towers;
+	Vec *moves;
+} day5_Data;
+
+static Move* day5_parse_move(char *line)
+{
+	char* line_copy = strdup(line);
+	char* line_copy_original = line_copy;
+	strsep(&line_copy, " ");
+	char* amount = strsep(&line_copy, " ");
+	strsep(&line_copy, " ");
+	char* from = strsep(&line_copy, " ");
+	strsep(&line_copy, " ");
+	char* to = strsep(&line_copy, " ");
+
+	Move *move = malloc(sizeof(Move));
+	move->amount = atoi(amount);
+	move->from = atoi(from)-1;
+	move->to = atoi(to)-1;
+	free(line_copy);
+	return move;
+}
+
+static void *day5_parse(char **lines, int line_count)
+{
+	int tower_count = 0;
+	int max_tower_height;
+
+	for (int i = 0; i < line_count; i++) {
+		if (lines[i][0] == '\0') {
+			max_tower_height = i-1;
+			break;
+		}
+
+		tower_count = MAX(tower_count, (strlen(lines[i])+1)/4);
+	}
+
+	int move_count = line_count - max_tower_height - 2;
+	Vec *moves = vec_malloc(move_count);
+	for (int i = 0; i < move_count; i++) {
+		char *line = lines[max_tower_height+2+i];
+		vec_push(moves, day5_parse_move(line));
+	}
+
+	Vec *towers = vec_malloc(tower_count);
+	for (int i = 0; i < tower_count; i++) {
+		char* tower = calloc(26, sizeof(char));
+		vec_push(towers, tower);
+	}
+	for (int i = max_tower_height-1; i >= 0; i--) {
+		char* line = lines[i];
+		int line_size = strlen(line);
+		for (int j = 0; j < tower_count; j++) {
+			int index = j*4 + 1;
+			if (index >= line_size) break;
+			if (line[index] == ' ') continue;
+
+			char* tower = towers->data[j];
+			tower[max_tower_height-i-1] = line[index];
+		}
+	}
+
+	day5_Data *data = malloc(sizeof(day5_Data));
+	data->moves  = moves;
+	data->towers = towers;
+	return data;
+}
+
+static void do_move(char **towers, int *tower_sizes, int from, int to)
+{
+	int from_size = tower_sizes[from];
+	int to_size = tower_sizes[to];
+	towers[to][to_size] = towers[from][from_size-1];
+
+	tower_sizes[from]--;
+	tower_sizes[to]++;
+}
+
+static void do_move_many(char **towers, int *tower_sizes, int from, int to, int amount)
+{
+	int from_size = tower_sizes[from];
+	int to_size = tower_sizes[to];
+	memcpy(towers[to] + to_size, towers[from] + from_size - amount, amount);
+
+	tower_sizes[from] -= amount;
+	tower_sizes[to]  += amount;
+}
+
+static char* form_answer(char **towers, int tower_count, int *tower_sizes)
+{
+	char *answer = malloc(tower_count + 1);
+	answer[tower_count] = '\0';
+	for (int i = 0; i < tower_count; i++) {
+		char *tower = towers[i];
+		answer[i] = tower[tower_sizes[i]-1];
+	}
+	return answer;
+}
+
+static void day5_part1(void *p)
+{
+	day5_Data *data = p;
+	int tower_count = data->towers->count;
+	char *towers[tower_count];
+	int tower_sizes[tower_count];
+	for (int i = 0; i < tower_count; i++) {
+		towers[i] = calloc(26, sizeof(char));
+		memcpy(towers[i], data->towers->data[i], 26);
+
+		tower_sizes[i] = 0;
+		for (int j = 0; j < 26; j++) {
+			if (towers[i][j] == 0) break;
+			tower_sizes[i]++;
+		}
+	}
+
+	for (int i = 0; i < data->moves->count; i++) {
+		Move *move = data->moves->data[i];
+		for (int j = 0; j < move->amount; j++) {
+			do_move(towers, tower_sizes, move->from, move->to);
+		}
+	}
+
+	printf("%s\n", form_answer(towers, tower_count, tower_sizes));
+}
+
+static void day5_part2(void *p)
+{
+	day5_Data *data = p;
+	int tower_count = data->towers->count;
+	char *towers[tower_count];
+	int tower_sizes[tower_count];
+	for (int i = 0; i < tower_count; i++) {
+		towers[i] = calloc(26, sizeof(char));
+		memcpy(towers[i], data->towers->data[i], 26);
+
+		tower_sizes[i] = 0;
+		for (int j = 0; j < 26; j++) {
+			if (towers[i][j] == 0) break;
+			tower_sizes[i]++;
+		}
+	}
+
+	for (int i = 0; i < data->moves->count; i++) {
+		Move *move = data->moves->data[i];
+		do_move_many(towers, tower_sizes, move->from, move->to, move->amount);
+	}
+
+	printf("%s\n", form_answer(towers, tower_count, tower_sizes));
+}
+
+ADD_SOLUTION(5, day5_parse, day5_part1, day5_part2);

main.c

@@ -12,6 +12,7 @@
 #include "day2.c"
 #include "day3.c"
 #include "day4.c"
+#include "day5.c"
 
 Solution *find_solution(int day)
 {
@@ -156,8 +157,10 @@ int main(int argc, char** argv) {
 
 	void* parsed = solution->parse(lines, line_count);
 
-	printf("part1: %d\n", solution->part1(parsed));
-	printf("part2: %d\n", solution->part2(parsed));
+	printf("part1:\n");
+	solution->part1(parsed);
+	printf("part2:\n");
+	solution->part2(parsed);
 
 	return 0;
 }