#define _GNU_SOURCE #include #include #include #include #include #define ISDIGIT(c) (c >= 0x30 && c <= 0x39) int main(int argc, char **argv) { FILE *input; char *line = NULL; size_t line_length = 0; if (argc == 1 || argv[1][0] == '-') input = stdin; else if ((input = fopen(argv[1], "r")) == NULL) { printf("Cannot open file %s\n", argv[1]); return -1; } char **engine = NULL; ssize_t engine_line_size = 0; ssize_t engine_lines = 0; while (getline(&line, &line_length, input) != -1) { ssize_t len = strlen(line)-1; if (engine == NULL) { engine = (char **) calloc(len, sizeof(char*)); engine_line_size = len; } engine[engine_lines] = (char*) calloc(len, sizeof(char)); memcpy(engine[engine_lines], line, len); ++engine_lines; memset(line, 0, line_length); } int32_t part_number = 0; int32_t n = 0; int32_t multiplier = 1; bool adjacent = false; for (ssize_t i = engine_lines-1; i >= 0; --i) { for (ssize_t j = engine_line_size-1; j >= 0; --j) { if (ISDIGIT(engine[i][j])) { n += (engine[i][j]&0xf) * multiplier; multiplier *= 10; if (adjacent == false && ((j+1 <= engine_line_size-1 && !ISDIGIT(engine[i][j+1]) && engine[i][j+1] != '.') || (j-1 >=0 && !ISDIGIT(engine[i][j-1]) && engine[i][j-1] != '.') || (i+1 <= engine_lines-1 && !ISDIGIT(engine[i+1][j]) && engine[i+1][j] != '.') || (i-1 >= 0 && !ISDIGIT(engine[i-1][j]) && engine[i-1][j] != '.') || ((i+1 <= engine_lines-1 && j+1 <= engine_line_size-1) && !ISDIGIT(engine[i+1][j+1]) && engine[i+1][j+1] != '.') || ((i+1 <= engine_lines-1 && j-1 >= 0) && !ISDIGIT(engine[i+1][j-1]) && engine[i+1][j-1] != '.') || ((i-1 >= 0 && j+1 <= engine_line_size-1) && !ISDIGIT(engine[i-1][j+1]) && engine[i-1][j+1] != '.') || ((i-1 >= 0 && j-1 >= 0) && !ISDIGIT(engine[i-1][j-1]) && engine[i-1][j-1] != '.'))) { adjacent = true; } } if ((!ISDIGIT(engine[i][j]) || j == 0) && n != 0) { if (adjacent) part_number += n; n = 0; multiplier = 1; adjacent = false; } } } for (ssize_t i = 0; i < engine_lines; ++i) free(engine[i]); free(engine); printf("%d\n", part_number); return 0; }