diff options
| -rw-r--r-- | 2020/day10.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/2020/day10.c b/2020/day10.c new file mode 100644 index 0000000..789f2b1 --- /dev/null +++ b/2020/day10.c @@ -0,0 +1,24 @@ +#include <stdio.h> +#include <stdlib.h> +static int compar(const void *_a, const void *_b) { + const int *a = _a; + const int *b = _b; + return *a - *b; +} +int main(void) { + int list[256]; + int len = 0; + while (EOF != scanf("%d\n", &list[len])) { + len++; + } + list[len++] = 0; + qsort(list, len, sizeof(int), compar); + list[len] = list[len-1] + 3; + len++; + int j1 = 0, j3 = 0; + for (int i = 1; i < len; ++i) { + if (list[i] - list[i-1] == 1) j1++; + if (list[i] - list[i-1] == 3) j3++; + } + printf("%d\n", j1 * j3); +} |