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advent-of-code/2021/day03/aoc-c.c

108 lines
2.3 KiB
C

/* aoc-c: Advent2021 game, day 2 parts 1 & 2
*
* Copyright (C) 2021 Bruno Raoult ("br")
* Licensed under the GNU General Public License v3.0 or later.
* Some rights reserved. See COPYING.
*
* You should have received a copy of the GNU General Public License along with this
* program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.htmlL>.
*
* SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <malloc.h>
#include "debug.h"
#include "bits.h"
static int ex1()
{
u32 length, gamma = 0, epsilon = 0;
char buffer[80];
s32 *values;
/* get length of binary number */
scanf("%s", buffer);
length = strlen(buffer);
values = calloc(length, sizeof(*values));
do {
for (u32 i = 0; i < length; ++i) {
switch (buffer[i]) {
case '0':
values[i]--;
break;
case '1':
values[i]++;
break;
}
}
} while (scanf("%s", buffer) != EOF);
for (u32 i = 0; i < length; ++i) {
if (values[i] > 0)
gamma += 1 << (length-i-1);
else
epsilon += 1 << (length-i-1);
}
free (values);
return gamma * epsilon;
}
static int ex2()
{
/* idea : Given 3 bits input
* 101
* 010
* 110
*
* we create an ushort array of size 2⁴ initialized at 2⁴
*
*/
return 1;
}
static int usage(char *prg)
{
fprintf(stderr, "Usage: %s [-d debug_level] [-p part]\n", prg);
return 1;
}
int main(int ac, char **av)
{
int opt;
u32 exercise = 1, res;
while ((opt = getopt(ac, av, "d:p:")) != -1) {
switch (opt) {
case 'd':
debug_level_set(atoi(optarg));
break;
case 'p': /* 1 or 2 */
exercise = atoi(optarg);
break;
default:
return usage(*av);
}
}
if (optind < ac)
return usage(*av);
if (exercise == 1) {
res = ex1();
printf ("%s : res=%d\n", *av, res);
}
if (exercise == 2) {
res = ex2();
printf ("%s : res=%d\n", *av, res);
}
exit (0);
}