100 lines
2.2 KiB
C
100 lines
2.2 KiB
C
/* aoc-c.c: Advent of Code 2019, day 3 parts 1 & 2
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*
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* Copyright (C) 2021 Bruno Raoult ("br")
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* Licensed under the GNU General Public License v3.0 or later.
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* Some rights reserved. See COPYING.
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*
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* You should have received a copy of the GNU General Public License along with this
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* program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
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*
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* SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <malloc.h>
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#include <errno.h>
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#include <string.h>
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#include <getopt.h>
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#include "debug.h"
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static int is_valid(int number, int part)
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{
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int valid = 0, dups[10] = { 0 };
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int digit, dec;
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for (digit = number % 10; number > 10; digit = dec) {
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number /= 10;
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dec = number % 10;
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if (dec > digit)
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return 0;
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if (dec == digit) {
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valid = 1;
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dups[digit] += 2;
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}
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}
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if (!valid || part == 1)
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return valid;
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for (int i = 0; i < 10; ++i)
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if (dups[i] == 2)
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return 1;
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return 0;
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}
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static int doit(int *nums, int part)
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{
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int res = 0;
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/* There is surely a way to avoid 99% of useless calls to is_valid.
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*/
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for (int i = nums[0]; i < nums[1]; ++i)
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if (is_valid(i, part))
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res++;
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return res;
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}
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static int *parse(int *res)
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{
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size_t alloc = 0;
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char *buf = NULL;
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getline(&buf, &alloc, stdin);
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*res = atoi(strtok(buf, "-"));
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*(res+1) = atoi(strtok(NULL, "-"));
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free(buf);
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return res;
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}
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static int usage(char *prg)
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{
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fprintf(stderr, "Usage: %s [-d debug_level] [-p part]\n", prg);
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return 1;
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}
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int main(int ac, char **av)
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{
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int opt, part = 1;
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int nums[2];
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while ((opt = getopt(ac, av, "d:p:")) != -1) {
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switch (opt) {
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case 'd':
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debug_level_set(atoi(optarg));
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break;
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case 'p': /* 1 or 2 */
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part = atoi(optarg);
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if (part < 1 || part > 2)
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default:
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return usage(*av);
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}
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}
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if (optind < ac)
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return usage(*av);
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parse(nums);
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printf("%s : res=%d\n", *av, doit(nums, part));
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exit (0);
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}
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