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#include "allocator.h"
#include "aoc.h"
#include "hmap.h"
#include "hmap_s.h"
#include "vec_s.h"
#include "util.h"
#include "list.h"
#include <assert.h>
#include <ctype.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#define PORTAL_ID(a, b) ((size_t) ((uint8_t) (a) * 100 + (uint8_t) (b)))
struct djk_state {
size_t dist;
struct vec2i pos;
struct list_link link;
};
static bool
djk_dist_ordering(const void *p1, const void *p2, void *u)
{
const struct djk_state *s1 = p1, *s2 = p2;
return s1->dist < s2->dist;
}
static void
load_map(struct hmap *map, const char *input, size_t len)
{
char line[256];
const char *lpos, *lend;
struct vec2i pos, *key;
lpos = aoc.input;
lend = lpos + aoc.input_size;
vec2i_setv(&pos, 0, 0);
while (readtok(line, sizeof(line), '\n', &lpos, lend)) {
for (pos.x = 0; line[pos.x]; pos.x++) {
if (line[pos.x] == ' ')
continue;
key = malloc(sizeof(struct vec2i));
vec2i_set(key, &pos);
hmap_add(map, (struct hmap_key) {.p = key},
(struct hmap_val) {.c = line[pos.x]});
}
pos.y += 1;
}
}
static void
load_portals(struct hmap *portals, struct hmap *map)
{
struct hmap_link *link1;
struct hmap_link *link2;
struct hmap_iter iter;
struct vec2i pos;
struct vec2i npos;
struct vec2i *key;
size_t i, id;
for (HMAP_ITER(map, iter)) {
if (!isupper(iter.link->value.c))
continue;
vec2i_set(&pos, iter.link->key.p);
for (i = 0; i < 4; i++) {
vec2i_add(&npos, &pos, &adj[i]);
link1 = hmap_get(map, (struct hmap_key) {.p = &npos});
if (link1 && isupper(link1->value.c))
break;
}
if (i != ADJ_SOUTH && i != ADJ_EAST)
continue;
for (i = 0; i < 4; i++) {
vec2i_add(&npos, &pos, &adj[i]);
link2 = hmap_get(map, (struct hmap_key) {.p = &npos});
if (link2 && link2->value.c == '.')
break;
}
if (i == 4) {
for (i = 0; i < 4; i++) {
vec2i_add(&npos, link1->key.p, &adj[i]);
link2 = hmap_get(map, (struct hmap_key) {.p = &npos});
if (link2 && link2->value.c == '.')
break;
}
}
assert(i != 4);
aoc_debug("FOUND %c %c\n", iter.link->value.c, link1->value.c);
key = memdup(link2->key.p, sizeof(struct vec2i));
id = PORTAL_ID(iter.link->value.c, link1->value.c);
hmap_add(portals, (struct hmap_key) {.p = key},
(struct hmap_val) {.s = id});
}
}
static bool
get_portal(struct hmap *portals, struct vec2i *pos, struct vec2i *skip, size_t id)
{
struct hmap_iter iter;
for (HMAP_ITER(portals, iter)) {
if (skip && vec2i_eql(skip, iter.link->key.p))
continue;
if (iter.link->value.s == id) {
vec2i_set(pos, iter.link->key.p);
return true;
}
}
return false;
}
static void
add_djk_state(struct list *active, struct hmap *distmap,
struct hmap *portals, struct vec2i *pos, size_t dist)
{
struct hmap_link **hmap_linkp;
struct djk_state *nstate;
struct vec2i *key;
bool new;
hmap_linkp = hmap_link_pos(distmap, (struct hmap_key) {.p = pos});
if (!*hmap_linkp) {
key = memdup(pos, sizeof(struct vec2i));
*hmap_linkp = hmap_link_alloc(distmap,
(struct hmap_key) {.p = key},
(struct hmap_val) {.s = dist}, NULL);
new = true;
} else {
if (dist < (*hmap_linkp)->value.s) {
(*hmap_linkp)->value.s = dist;
new = true;
} else {
new = false;
}
}
if (new) {
nstate = malloc(sizeof(struct djk_state));
nstate->dist = dist;
vec2i_set(&nstate->pos, pos);
nstate->link = LIST_LINK_INIT;
list_insert_sorted(active, &nstate->link,
false, djk_dist_ordering,
LIST_OFFSET(struct djk_state, link), NULL);
}
}
static size_t
min_dist(struct hmap *map, struct hmap *portals,
struct vec2i *start, struct vec2i *end)
{
struct list active;
struct hmap distmap;
struct list_link *list_link;
struct hmap_link *hmap_link;
struct hmap_iter hmap_iter;
struct djk_state *state;
struct vec2i *key, npos;
size_t mdist, i;
list_init(&active);
hmap_init(&distmap, 256, vec2i_hmap_hash, vec2i_hmap_keycmp,
&stdlib_strict_heap_allocator);
state = malloc(sizeof(struct djk_state));
state->dist = 0;
vec2i_set(&state->pos, start);
list_insert_front(&active, &state->link);
key = memdup(start, sizeof(struct vec2i));
hmap_add(&distmap, (struct hmap_key) {.p = key},
(struct hmap_val) {.s = 0});
mdist = 0;
while (!list_empty(&active)) {
list_link = list_front(&active);
state = LIST_UPCAST(list_link, struct djk_state, link);
if (vec2i_eql(&state->pos, end)) {
mdist = state->dist;
goto exit;
}
list_link_pop(list_link);
hmap_link = hmap_get(&distmap, (struct hmap_key) {.p = &state->pos});
assert(hmap_link);
if (state->dist != hmap_link->value.s) {
free(state);
continue;
}
hmap_link = hmap_get(portals, (struct hmap_key) {.p = &state->pos});
if (hmap_link) {
if (get_portal(portals, &npos, &state->pos, hmap_link->value.s))
add_djk_state(&active, &distmap, portals,
&npos, state->dist + 1);
}
for (i = 0; i < 4; i++) {
vec2i_add(&npos, &state->pos, &adj[i]);
hmap_link = hmap_get(map, (struct hmap_key) {.p = &npos});
if (!hmap_link || hmap_link->value.c != '.') continue;
add_djk_state(&active, &distmap, portals,
&npos, state->dist + 1);
}
free(state);
}
exit:
for (HMAP_ITER(&distmap, hmap_iter))
free(hmap_iter.link->key._p);
hmap_deinit(&distmap);
list_free_items(&active, free, LIST_OFFSET(struct djk_state, link));
return mdist;
}
void
part1(void)
{
struct hmap map;
struct hmap portals;
struct hmap_iter iter;
struct vec2i start, end;
size_t answer;
hmap_init(&map, 256, vec2i_hmap_hash, vec2i_hmap_keycmp,
&stdlib_strict_heap_allocator);
hmap_init(&portals, 256, vec2i_hmap_hash, vec2i_hmap_keycmp,
&stdlib_strict_heap_allocator);
load_map(&map, aoc.input, aoc.input_size);
load_portals(&portals, &map);
assert(get_portal(&portals, &start, NULL, PORTAL_ID('A', 'A')));
assert(get_portal(&portals, &end, NULL, PORTAL_ID('Z', 'Z')));
answer = min_dist(&map, &portals, &start, &end);
aoc.answer = aprintf("%lu", answer);
aoc.solution = "656";
for (HMAP_ITER(&portals, iter))
free(iter.link->key._p);
hmap_deinit(&portals);
for (HMAP_ITER(&map, iter))
free(iter.link->key._p);
hmap_deinit(&map);
}
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