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

int main() {
  FILE* input = fopen("../data/2017/1/input.txt", "r");
  char c1, c2, first_char;
  long total;

  fread(&first_char, 1, 1, input);
  c2 = first_char;

  while (fread(&c1, 1, 1, input) > 0 && c1 != '\n') {
    if (c1 == c2) {
      total += c1 - '0';
    }
    c2 = c1;
  }

  if (c2 == first_char) {
    total += c2 - '0';
  }

  printf("Part 1: %d\n", total);

  int num_chars = ftell(input);
  rewind(input);
  total = 0;

  char *buffer = malloc(num_chars);
  fread(buffer, 1, num_chars, input);

  for(int i = 0; i < num_chars / 2; i++) {
    c1 = buffer[i];
    c2 = buffer[i + (num_chars / 2)];
    if (c1 == c2) {
      total += c1 - '0';
    }
  }

  total <<= 1;

  printf("Part 2: %d\n", total);
}