AdventOfCode/02/src/main.c

/**
 * Copyright [2023] Jiří Štefka <jiriks74>
 * Project: AdventOfCode
 * @file main.c
 * @brief Main entry point
 * @author jiriks74
 */

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

const int MAX_RED = 12;
const int MAX_GREEN = 13;
const int MAX_BLUE = 14;

typedef struct {
  int red;
  int green;
  int blue;
} GameShow;

/**
 * @brief Count how many cubes of each color were in a show
 * @param *show A show of cubes in a game
 * @return A count of all the cubes in a struct
 */
GameShow get_max_cube_counts(char *game) {
  char *curr = game;
  GameShow result = {0};

  while (curr != NULL) {
    char *end_show = strchr(curr, ';');

    if (end_show != NULL) {
      *end_show = '\0';
    }

    while (curr != NULL) {
      int cube_count = atoi(curr);

      curr = strchr(curr, ' ');
      curr += sizeof(char);

      if (*curr == 'r') {
        if (cube_count > result.red)
          result.red = cube_count;
      } else if (*curr == 'g') {
        if (cube_count > result.green)
          result.green = cube_count;
      } else if (*curr == 'b') {
        if (cube_count > result.blue)
          result.blue = cube_count;
      } else {
        result.red = -1;
        result.green = -1;
        result.blue = -1;
        return result;
      }
      curr = strchr(curr, ',');
      if (curr != NULL)
        curr += sizeof(char) * 2;
    }

    if (end_show != NULL) {
      *end_show = ';';
      curr = end_show + sizeof(char) * 2;
    } else
      curr = end_show;
  }
  return result;
}

/**
 * @brief Count how many times were the cubes shown
 * @return Number of shows or -1 when error occurs
 */
bool is_game_possible(char *game) {
  // char *curr = strchr(game, ':');
  // curr += sizeof(char) * 2;

  // if (curr == NULL) {
  //   return false;
  // }

  GameShow show_counts = get_max_cube_counts(game);

  if (show_counts.red > MAX_RED)
    return false;
  else if (show_counts.green > MAX_GREEN)
    return false;
  else if (show_counts.blue > MAX_BLUE)
    return false;

  return true;
}

#ifndef TESTING
/**
 * @brief Main entry point
 * @param argc Number of command-line arguments.
 * @param argv Array of command-line arguments.
 */
int main(int argc, char *argv[])
#endif
#ifdef TESTING
    int main_test(int argc, char *argv[])
#endif
{
  FILE *input = fopen(argv[1], "r");

  int possible_game_ids_sum = 0;
  int sum_of_powers = 0;

  char line[512];
  while (fgets(line, sizeof(line), input)) {
    if (*line != 'G')
      break;

    int curr_game_id = atoi(line + sizeof("Game"));

    // if (is_game_possible(line)) {
    if (is_game_possible(strchr(line, ':') + sizeof(char) * 2)) {
      possible_game_ids_sum += curr_game_id;
      // printf("Game %d is possible\n", curr_game_id);
    } // else
      // printf("Game %d is impossible\n", curr_game_id);
    GameShow min_cubes =
        get_max_cube_counts(strchr(line, ':') + sizeof(char) * 2);
    sum_of_powers += min_cubes.red * min_cubes.green * min_cubes.blue;
  }

  printf("Sum of possible game IDs: %d\n", possible_game_ids_sum);
  printf("Sum of powers:            %d\n", sum_of_powers);
  return 0;
}