solve day 10

day10.c

@@ -0,0 +1,126 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "aoc.h"
+
+typedef enum {
+	INST_TYPE_NOOP,
+	INST_TYPE_ADD,
+} INST_TYPE;
+
+typedef struct {
+	INST_TYPE type;
+	int amount;
+} Instruction;
+
+typedef struct {
+	Instruction *instructions;
+	int count;
+} day10_Data;
+
+static void *day10_parse(char **lines, int line_count)
+{
+	day10_Data *data = malloc(sizeof(day10_Data));
+	data->count = line_count;
+	data->instructions = malloc(line_count * sizeof(Instruction));
+
+	for (int i = 0; i < line_count; i++) {
+		char *line = lines[i];
+		Instruction *inst = &data->instructions[i];
+		if (!strcmp(line, "noop")) {
+			inst->type = INST_TYPE_NOOP;
+		} else { // addx
+			inst->type = INST_TYPE_ADD;
+			inst->amount = atoi(line + 5);
+		}
+	}
+
+	return data;
+}
+
+static void day10_part1(void *p)
+{
+	day10_Data *data = p;
+
+	int regx = 1;
+	int result = 0;
+	int inst_idx = 0;
+	int cycle = 0;
+	int add_timer = 0;
+	bool add_started = false;
+	while (inst_idx < data->count) {
+		Instruction *inst = &data->instructions[inst_idx];
+		if (!add_started) {
+			if (inst->type == INST_TYPE_NOOP) {
+				inst_idx++;
+			} else if (inst->type == INST_TYPE_ADD) {
+				add_started = true;
+				add_timer = 2;
+			}
+		}
+
+		cycle++;
+
+		if ((cycle - 20) % 40 == 0 && cycle <= 220) {
+			result += cycle*regx;
+		}
+
+		if (add_started) {
+			add_timer--;
+			if (add_timer == 0) {
+				add_started = false;
+				regx += inst->amount;
+				inst_idx++;
+			}
+		}
+	}
+
+	printf("%d\n", result);
+}
+
+static void day10_part2(void *p)
+{
+	day10_Data *data = p;
+
+	int regx = 1;
+	int inst_idx = 0;
+	int cycle = 0;
+	int add_timer = 0;
+	bool add_started = false;
+	while (inst_idx < data->count) {
+		Instruction *inst = &data->instructions[inst_idx];
+		if (!add_started) {
+			if (inst->type == INST_TYPE_NOOP) {
+				inst_idx++;
+			} else if (inst->type == INST_TYPE_ADD) {
+				add_started = true;
+				add_timer = 2;
+			}
+		}
+
+		if (abs(cycle % 40 - regx) <= 1) {
+			printf("#");
+		} else {
+			printf(".");
+		}
+
+		cycle++;
+
+		if (add_started) {
+			add_timer--;
+			if (add_timer == 0) {
+				add_started = false;
+				regx += inst->amount;
+				inst_idx++;
+			}
+		}
+
+		if (cycle % 40 == 0) {
+			printf("\n");
+		}
+	}
+}
+
+ADD_SOLUTION(10, day10_parse, day10_part1, day10_part2);

main.c

@@ -17,6 +17,7 @@
 #include "day7.c"
 #include "day8.c"
 #include "day9.c"
+#include "day10.c"
 
 Solution *find_solution(int day)
 {