2017/advent4.c

   1 #define _GNU_SOURCE 1
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <stdlib.h>
   5
   6 int sorter(const void *a, const void *b) {
   7   return *(unsigned char *)a - *(unsigned char *)b;
   8 }
   9
  10 int main(void) {
  11   ssize_t nread;
  12   size_t len = 0;
  13   char *line = NULL;
  14   int sum = 0;
  15   while ((nread = getline(&line, &len, stdin)) >= 0) {
  16     char *cur = line;
  17     char *space;
  18     line[nread - 1] = ' ';
  19     sum++;
  20 #if 1 // part 2
  21     while ((space = memchr(cur, ' ', line + nread - cur))) {
  22       qsort(cur, space - cur, 1, sorter);
  23       cur = space + 1;
  24     }
  25     cur = line;
  26 #endif
  27     while ((space = strchr(cur, ' '))) {
  28       if (space - line == nread - 1)
  29         break;
  30       char *candidate = space;
  31       while ((candidate = memmem(candidate + 1, line + nread - candidate - 1,
  32                                  cur, space - cur + 1))) {
  33         if (candidate[-1] == ' ') {
  34           goto skip;
  35         }
  36       }
  37       cur = space + 1;
  38     }
  39     continue;
  40   skip:
  41     sum--;
  42   }
  43   free (line);
  44   printf("%d\n", sum);
  45 }