#define _GNU_SOURCE #include #include #include #include #define ISDIGIT(c) (c >= 0x30 && c <= 0x39) inline uint64_t parse_number(const char *end); int main(int argc, char **argv) { FILE *input; size_t line_buf_length = 0; if (argc == 1 || argv[1][0] == '-') input = stdin; else if ((input = fopen(argv[1], "r")) == NULL) { fprintf(stderr, "Cannot open file %s\n", argv[1]); return -1; } char *time_line = NULL, *distance_line = NULL; ssize_t time_line_length = 0, distance_line_length = 0; if ((time_line_length = getline(&time_line, &line_buf_length, input)) == -1) { fprintf(stderr, "No time line in a file %s.", argv[1]); return -1; } if ((distance_line_length = getline(&distance_line, &line_buf_length, input)) == -1) { fprintf(stderr, "No distance line in a file %s.", argv[1]); return -1; } uint64_t *times = (uint64_t *) calloc(2, sizeof(uint64_t)); uint64_t *distances = (uint64_t *) calloc(2, sizeof(uint64_t)); ssize_t times_length = 2, distances_length = 2; for (ssize_t i = time_line_length-2, j = 0;;) { while (!ISDIGIT(time_line[i])) if (time_line[--i] == ':') goto tl_end; if (j == times_length) times = (uint64_t *) realloc(times, ++times_length * sizeof(uint64_t)); times[j++] = parse_number(time_line+i); while(ISDIGIT(time_line[i])) --i; } tl_end: for (ssize_t i = distance_line_length-2, j = 0;;) { while (!ISDIGIT(distance_line[i])) if (distance_line[--i] == ':') goto dl_end; if (j == distances_length) distances = (uint64_t *) realloc(distances, ++distances_length * sizeof(uint64_t)); distances[j++] = parse_number(distance_line+i); while(ISDIGIT(distance_line[i])) --i; } dl_end: uint64_t total_ways = 1; for (ssize_t i = 0; i < times_length; ++i) { uint64_t tmid = times[i] / 2; uint64_t ways = 0; for (uint64_t ht = tmid; ht <= times[i]; ++ht) if (ht * (times[i] - ht) > distances[i]) ++ways; else break; for (uint64_t ht = tmid-1; ht != 0; --ht) if (ht * (times[i] - ht) > distances[i]) ++ways; else break; total_ways *= ways; } free(times); free(distances); printf("%lu\n", total_ways); return 0; } inline uint64_t parse_number(const char *end) { uint64_t num = 0; for (size_t m = 1;; m *= 10) { if (*end>>4 != 0x3) break; num += (*end&0xf) * m; --end; } return num; }