2017/advent2.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4
   5 #if 0 // part 1
   6
   7 int main(void) {
   8   ssize_t nread;
   9   size_t len = 0;
  10   char *line = NULL;
  11   int sum = 0;
  12   while ((nread = getline(&line, &len, stdin)) >= 0) {
  13     unsigned int min = -1, max = 0;
  14     char *token = strtok(line, " \t");
  15     while (token) {
  16       int value = atoi(token);
  17       if (value < min)
  18         min = value;
  19       if (value > max)
  20         max = value;
  21       token = strtok(NULL, " \t");
  22     }
  23     sum += max - min;
  24   }
  25   printf("%d\n", sum);
  26 }
  27
  28 #else // part 2
  29
  30 int main(void) {
  31   ssize_t nread;
  32   size_t len = 0;
  33   char *line = NULL;
  34   int sum = 0;
  35   while ((nread = getline(&line, &len, stdin)) >= 0) {
  36     int *array = calloc(sizeof(int), nread);
  37     char *token = strtok(line, " \t");
  38     int i = 0, j;
  39     while (token) {
  40       array[i++] = atoi(token);
  41       token = strtok(NULL, " \t");
  42     }
  43     for (i = 0; i < nread; i++) {
  44       if (!array[i])
  45         continue;
  46       for (j = 0; j < nread; j++) {
  47         if (i == j || !array[j])
  48           continue;
  49         if (!(array[i] % array[j])) {
  50           sum += array[i] / array[j];
  51           printf("found %d/%d=%d\n", array[i], array[j], array[i]/array[j]);
  52           goto done;
  53         }
  54       }
  55     }
  56   done:
  57     ;
  58   }
  59   printf("%d\n", sum);
  60 }
  61
  62 #endif