day 25, first version (need lots of cleaning)

2021/day25/aoc-c.c

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+/* aoc-c.c: Advent of Code 2021, day 25 part 1
+ *
+ * Copyright (C) 2022 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>
+ */
+
+/* Warning: Work in progress. Should not work before I spend a lot of time
+ * on it, the original "bitboard" approach for moves generation is pretty
+ * difficult to program/debug
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "pool.h"
+#include "debug.h"
+#include "bits.h"
+#include "list.h"
+
+
+struct map {
+    int ncols, nrows;
+    char *map, *next;
+};
+
+static inline char *mapline(struct  map *m, int row)
+{
+    return m->map + row * m->ncols + row;
+}
+static inline char *nextline(struct  map *m, int row)
+{
+    return m->next + row * m->ncols + row;
+}
+static inline char *mapc(struct  map *m, int row, int col)
+{
+    return mapline(m, row) + col;
+}
+static inline char* nextc(struct  map *m, int row, int col)
+{
+    return nextline(m, row) + col;
+}
+
+/*
+static void print_map(struct map *map)
+{
+    int i;
+    printf ("map: cols=%d rows=%d\ncur:\n", map->ncols, map->nrows);
+    for  (i = 0; i < map->nrows; ++i)
+        puts(mapline(map, i));
+    printf ("next:\n");
+    for  (i = 0; i < map->nrows; ++i)
+        puts(nextline(map, i));
+}
+*/
+
+static int step(struct map *map)
+{
+    int r, c, mod = map->ncols, moves=0;
+    char *tmp;
+
+    /* move right */
+    for (r = 0; r < map->nrows; r++) {
+        for (c = 0; c < map->ncols; ++c) {
+            int next = (c + 1) % mod;
+            if (*mapc(map, r, c) == '>' && *mapc(map, r, next) == '.') {
+                *nextc(map, r, c) = '.';
+                *nextc(map, r, next) = '>';
+                moves++;
+                c++;
+            } else {
+                *nextc(map, r, c) = *mapc(map, r, c);
+            }
+        }
+    }
+    tmp = map->map;
+    map->map = map->next;
+    map->next = tmp;
+
+    /* move down */
+    mod = map->nrows;
+    for (c = 0; c < map->ncols; ++c) {
+        for (r = 0; r < map->nrows; r++) {
+            int next = (r + 1) % mod;
+            if (*mapc(map, r, c) == 'v' && *mapc(map, next, c) == '.') {
+                *nextc(map, r, c) = '.';
+                *nextc(map, next, c) = 'v';
+                moves++;
+                r++;
+            } else {
+                *nextc(map, r, c) = *mapc(map, r, c);
+            }
+        }
+    }
+    tmp = map->map;
+    map->map = map->next;
+    map->next = tmp;
+    //print_map(map);
+    return moves;
+}
+
+/* minimal parsing: We just read the 3-5 lines to get
+ * the amphipods location in side rooms
+ */
+static void read_input(struct map *map)
+{
+    size_t alloc = 0;
+    ssize_t buflen;
+    char *buf = NULL;
+    int line = 0;
+
+    buflen = getline(&buf, &alloc, stdin);
+    buf[buflen - 1] = 0;
+    map->map = malloc(buflen * buflen);
+    map->next = malloc(buflen * buflen);
+    map->ncols = buflen - 1;
+    strcpy(map->map, buf);
+    strcpy(map->next, buf);
+    line++;
+    free(buf);
+    buf = mapline(map, line);
+    while (fgets(buf, buflen + 1, stdin)) {
+        buf[buflen - 1] = 0;
+        strcpy(nextline(map, line), buf);
+        line++;
+        buf = mapline(map, line);
+    }
+    map->nrows = line;
+}
+
+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, part = 1, moves, cur=1;
+    struct map map = { 0, 0, NULL, NULL};
+
+    while ((opt = getopt(ac, av, "d:p:")) != -1) {
+        switch (opt) {
+            case 'd':
+                debug_level_set(atoi(optarg));
+                break;
+            case 'p':                             /* 1 or 2 */
+                part = atoi(optarg);
+                if (part < 1 || part > 2)
+                    return usage(*av);
+                break;
+            default:
+                return usage(*av);
+        }
+    }
+    if (optind < ac)
+        return usage(*av);
+
+    read_input(&map);
+    while ((moves = step(&map))) {
+        cur++;
+    }
+
+    printf("%s : res=%d\n", *av, cur);
+
+    exit(0);
+}