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advent-of-code/2021/day10/aoc-c.c

165 lines
3.6 KiB
C

/* aoc-c: Advent2021 game, day 6 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.html>.
*
* 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 char stack[1024];
static size_t nstack;
struct match {
char open;
char close;
int value_corrupted;
int value_incomplete;
} syntax[] = {
{ '(', ')', 3, 1 },
{ '[', ']', 57, 2 },
{ '{', '}', 1197, 3 },
{ '<', '>', 25137, 4 }
};
inline static int push(char c)
{
return ((stack[nstack++] = c));
}
inline static int pop()
{
if (!nstack)
return 0;
return (stack[--nstack]);
}
static s64 match_corrupted(char c)
{
int co;
s64 res = 0;
if ((co = pop())) {
for (size_t i = 0; i < sizeof(syntax) / sizeof(struct match); ++i) {
if (syntax[i].close == c && co != syntax[i].open) {
res = syntax[i].value_corrupted;
break;
}
}
}
return res;
}
static s64 match_incomplete()
{
int co;
s64 res = 0;
while ((co = pop())) {
for (size_t i = 0; i < sizeof(syntax) / sizeof(struct match); ++i) {
if (co == syntax[i].open) {
res = res * 5 + syntax[i].value_incomplete;
break;
}
}
}
return res;
}
static s64 *ins_sort(s64 *array, int n)
{
for (int i = 1, j = 0; i < n; i++, j = i - 1) {
s64 cur = array[i];
while (j >= 0 && array[j] > cur) {
array[j + 1] = array[j];
j = j - 1;
}
array[j + 1] = cur;
}
return array;
}
static s64 doit(int part)
{
char *buf = NULL, *p;
size_t alloc;
ssize_t len;
s64 res_corrupted = 0, inc[1024], tmp;
int ninc = 0;
while ((len = getline(&buf, &alloc, stdin)) > 0) {
nstack = 0;
buf[len - 1] = 0;
p = buf;
while (*p) {
switch (*p) {
case '{':
case '(':
case '[':
case '<':
push(*p);
break;
case '}':
case ')':
case ']':
case '>':
if ((tmp = match_corrupted(*p))) {
res_corrupted += tmp;
goto next;
}
}
p++;
}
inc[ninc++] = match_incomplete(0);
next:
}
free(buf);
return part == 1? res_corrupted : ins_sort(inc, ninc)[ninc / 2];
}
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;
s64 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);
if (exercise < 1 || exercise > 2)
return usage(*av);
break;
default:
return usage(*av);
}
}
if (optind < ac)
return usage(*av);
res = doit(exercise);
printf("%s : res=%lu\n", *av, res);
exit (0);
}