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advent-of-code/2022/day16/aoc-c.c

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/* aoc-c.c: Advent of Code 2022, day 16
*
* Copyright (C) 2023 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 <string.h>
#include "br.h"
#include "list.h"
#include "pool.h"
#include "debug.h"
#include "bits.h"
#include "aoc.h"
pool_t *pool_valve;
union val {
u32 val;
char str[3];
};
enum state {
CLOSED,
OPENED
};
struct worker {
struct valve *pos;
int depth;
int time;
};
struct valve {
int index; /* -1 for zero flow rate */
union val val;
enum state state;
int rate;
int evalflow, evaltime;
int playedflow, playedtime;
struct hlist_node hlist;
struct list_head index_sorted;
struct list_head flow_sorted;
struct list_head eval;
int worker;
struct list_head played;
int ntunnels, tottunnels;
struct valve **tunnels; /* array */
};
static struct graph {
struct valve *aa; /* head ("AA") */
int npositive; /* only "AA" & working valves */
int nvalves;
u64 opened; /* bitmask of opened valves */
u64 openable; /* bitmask of openable valves */
struct list_head index_sorted; /* TO REMOVE ? */
struct list_head flow_sorted;
struct list_head eval;
struct list_head played[2];
struct valve **indexed_all;
int *dist; /* 2-D array */
} graph = {
.aa = NULL,
.npositive = 0,
.nvalves = 0,
.index_sorted = LIST_HEAD_INIT(graph.index_sorted),
.flow_sorted = LIST_HEAD_INIT(graph.flow_sorted),
.eval = LIST_HEAD_INIT(graph.eval),
.played[0] = LIST_HEAD_INIT(graph.played[0]),
.played[1] = LIST_HEAD_INIT(graph.played[1]),
.indexed_all = NULL,
.dist = NULL
};
#define POS(a, b) ((a)*graph.nvalves + (b))
#define DIST(a, b) (graph.dist[POS((a), (b))])
static void print_valves()
{
struct valve *cur;
printf("**** graph: .head=%p npositive=%d\n", graph.aa, graph.npositive);
printf("index1: ");
list_for_each_entry(cur, &graph.index_sorted, index_sorted) {
printf("%d:%s ", cur->index, cur->val.str);
}
printf("\n");
printf("index2: ");
for (int i = 0; i < graph.nvalves; ++i) {
printf("%d:%s ", graph.indexed_all[i]->index, graph.indexed_all[i]->val.str);
}
printf("\n");
if (testmode()) {
printf("distances:\n ");
for (int i = 0; i < graph.nvalves; ++i) {
printf(" %s", graph.indexed_all[i]->val.str);
}
printf("\n");
for (int i = 0; i < graph.nvalves; ++i) {
printf("%s ", graph.indexed_all[i]->val.str);
for (int j = 0; j < graph.nvalves; ++j) {
printf("%5d ", DIST(i, j));
}
printf("\n");
}
}
printf("flow_sorted: ");
list_for_each_entry(cur, &graph.flow_sorted, flow_sorted) {
printf("%s:%d ", cur->val.str, cur->rate);
}
printf("\n");
printf("openable: %#lx ", graph.openable);
int pos, tmp;
bit_for_each64_2(pos, tmp, graph.openable) {
printf("%d ", pos);
}
printf("\n");
}
#define PAD3 log(3, "%*s", _depth * 2, "")
#define PAD4 log(4, "%*s", _depth * 2, "")
/**
* eval() - eval possible moves from @flow_sorted list.
* @_depth: recursivity depth (for debug only, TODO: remove).
* @nworkers: number of workers.
* @workers: array of workers.
* @pick: max position (in @flow_sorted) to pick moves from (-1 for all).
* @pressure: total pressure per time unit so far.
*
* Find the "best" next move by evaluating only the first @pick elements
* in @flow_sorted list.
*
* @Return: the current position eval.
*/
static struct valve *eval(int _depth, int nworkers, struct worker *worker, int pick, int pressure)
{
struct valve *cur, *best = NULL, *sub;
struct list_head *list_flow, *tmp;
int _pick = pick, val = 0, val1, max = 0, bestworker = -1;
int _nworkers = nworkers;
if (nworkers == 2 && worker[0].pos->index == worker[1].pos->index)
_nworkers = 1;
PAD3; log_f(3, "EVAL _depth=%d w0={ pos=%d[%s] depth=%d time=%d } w1={ pos=%d[%s] depth=%d time=%d } pick=%d pressure=%d \n",
_depth,
worker[0].pos->index, worker[0].pos->val.str,
worker[0].depth, worker[0].time,
worker[1].pos->index, worker[1].pos->val.str,
worker[1].depth, worker[1].time,
pick, pressure);
list_for_each_safe(list_flow, tmp, &graph.flow_sorted) {
cur = list_entry(list_flow, struct valve, flow_sorted);
//int nworkers = worker[0].pos->index == worker[1].pos->index? 1: 2;
if (!--_pick) {
PAD4; log(4, "pick exhausted\n");
break;
}
for (int _w = 0; _w < _nworkers; ++_w) {
struct worker *w = worker + _w;
int d = DIST(w->pos->index, cur->index);
int remain = w->time - (d + 1);
PAD3; log(3, "worker %d/%d ", _w + 1, nworkers );
PAD3; log(3, "dist(%s,%s) = %d ", w->pos->val.str, cur->val.str, d);
if (remain < 1) {
PAD3; log(4, "time exhausted\n");
continue;
}
val = remain * cur->rate;
PAD3; log(3, "--> val=%d\n", val);
if (w->depth > 0) {
struct worker _tmp = *w;
w->pos = cur;
w->depth--;
w->time = remain;
/* do not use list_del() here, to preserve prev/next pointers */
__list_del_entry(list_flow);
sub = eval(_depth + 1, nworkers, worker, pick, pressure + w->pos->rate);
list_flow->prev->next = list_flow;
list_flow->next->prev = list_flow;
*w = _tmp;
} else {
sub = NULL;
}
val1 = sub? sub->evalflow: 0;
PAD3; log(3, "eval3(%s->%s)= %5d = %d + %d", w->pos->val.str, cur->val.str,
val+val1, val, val1);
if (val + val1 > max) {
max = val + val1;
best = cur;
bestworker = _w;
log(3, " NEW MAX !");
}
log(3, "\n");
}
}
if (best) {
best->evalflow = max;
best->worker = bestworker; /* FIXME */
PAD3; log(3, "EVAL returning best [%s] worker=%d eval=%d\n", best->val.str,
best->worker, max);
}
return best;
}
static struct valve *find_valve(union val val, int ntunnels, int rate)
{
struct valve *cur;
log_f(3, "val=%s ntunnels=%d rate=%d\n", val.str, ntunnels, rate);
list_for_each_entry(cur, &graph.index_sorted, index_sorted) {
//log(3, "\tcomparing with found, addr=%p\n", cur);
if (cur->val.val == val.val) {
log(3, "\tfound, addr=%p\n", cur);
if (ntunnels)
goto init;
goto end;
}
}
cur = pool_get(pool_valve);
cur->val.val = val.val;
cur->ntunnels = 0;
cur->state = CLOSED;
cur->worker = -1;
cur->evalflow = cur->playedflow = 0;
cur->evaltime = cur->playedtime = 30;
INIT_LIST_HEAD(&cur->index_sorted);
INIT_LIST_HEAD(&cur->flow_sorted);
INIT_LIST_HEAD(&cur->eval);
INIT_LIST_HEAD(&cur->played);
log(3, "\talloc new, addr=%p\n", cur);
init:
if (ntunnels) {
cur->rate = rate;
cur->tottunnels = ntunnels;
cur->tunnels = calloc(ntunnels, sizeof(struct valve *));
}
end:
return cur;
}
/**
* nthtok - get nth token fron string.
* @buf: buffer to parse.
* @sep: separators string.
* @n: token number (0: first token).
*
* @Return: pointer to token.
*/
static char *nthtok(char *buf, const char *sep, int n)
{
char *ret;
for (; n >= 0; n--) {
ret = strtok(buf, sep);
buf = NULL;
}
return ret;
}
#define SEP " ,;="
static struct graph *parse()
{
int index = 0, ntunnels;
size_t alloc = 0;
ssize_t buflen;
char *buf = NULL, *tok;
int rate;
struct valve *v1, *v2;
union val cur, link;
while ((buflen = getline(&buf, &alloc, stdin)) > 0) {
buf[--buflen] = 0;
/* valve name */
strncpy(cur.str, nthtok(buf, SEP, 1), sizeof(cur.str));
//printf("valve=%s ", tok);
rate = atoi(nthtok(NULL, SEP, 3));
//printf("rate=%s ", tok);
tok = nthtok(NULL, SEP, 4);
ntunnels = (buf + buflen - tok) / 4 + 1;
v1 = find_valve(cur, ntunnels, rate);
v1->index = index++;
// TODO: remove this list ?
list_add_tail(&v1->index_sorted, &graph.index_sorted);
graph.nvalves++;
//if (rate || v1->val.val == ('A' << 8 | 'A')) {
if (rate) {
struct valve *cur;
graph.npositive++;
/* keep this list sorted by flow decrasing */
list_for_each_entry(cur, &graph.flow_sorted, flow_sorted) {
if (rate > cur->rate) {
list_add_tail(&v1->flow_sorted, &cur->flow_sorted);
goto inserted;
}
}
list_add_tail(&v1->flow_sorted, &graph.flow_sorted);
inserted: ;
if (rate) {
//printf("adjust openable(%d): %#lx", v1->index, graph.openable);
graph.openable |= (1 << v1->index);
//printf("->%#lx", graph.openable);
}
}
//printf("lead=%s ntunnels=%d ", tok, ntunnels);
do {
link.val = *(u16 *)tok;
v2 = find_valve(link, 0, 0);
*(v1->tunnels + v1->ntunnels++) = v2;
//printf(",%s", tok);
} while ((tok = nthtok(NULL, SEP, 0)));
//printf("\n");
}
graph.aa = find_valve((union val) { .str="AA" }, 0, 0);
/* build array of indexed valves */
graph.indexed_all = calloc(graph.nvalves, sizeof(struct valve *));
list_for_each_entry(v1, &graph.index_sorted, index_sorted) {
graph.indexed_all[v1->index] = v1;
}
return &graph;
}
static int is_neighbour(int i, int j)
{
struct valve *v1 = graph.indexed_all[i], *v2 = graph.indexed_all[j];
for (int i = 0; i < v1->ntunnels; ++i)
if (v1->tunnels[i]->val.val == v2->val.val)
return 1;
return 0;
}
static void build_distances()
{
int i, j, k;
graph.dist = calloc(graph.nvalves * graph.nvalves, sizeof(int));
/* initialize values */
for (i = 0; i < graph.nvalves; ++i) {
for (j = 1; j < graph.nvalves; ++j) {
if (i != j) {
if (is_neighbour(i, j))
DIST(i, j) = DIST(j, i) = 1;
else
DIST(i, j) = DIST(j, i) = 10000;
}
}
}
/* get all distances using Floyd-Warshall
* see https://en.wikipedia.org/wiki/Floyd%E2%80%93Warshall_algorithm
*
* Add all vertices one by one to the set of intermediate vertices.
* ---> Before start of an iteration, we have shortest distances between all
* pairs of vertices such that the shortest distances consider only the
* vertices in set {0, 1, 2, .. k-1} as intermediate vertices.
* ----> After the end of an iteration, vertex no. k is added to the set of
* intermediate vertices and the set becomes {0, 1, 2, .. k}
*/
for (k = 0; k < graph.nvalves; k++) {
/* Pick all vertices as source one by one */
for (i = 0; i < graph.nvalves; i++) {
/* Pick all vertices as destination for the above picked source */
for (j = i + 1; j < graph.nvalves; j++)
DIST(i, j) = DIST(j, i) = min(DIST(i, j), DIST(i, k) + DIST(k, j));
}
}
return;
}
static void print_played(int nworkers)
{
struct valve *p;
int total = 0;
for (int w = 0; w < nworkers; ++w) {
int remain = 26, i = 1;
struct valve *prev = graph.aa;
i = 1;
printf("played by %d/%d:\n", w + 1, nworkers);
list_for_each_entry(p, &graph.played[w], played) {
printf("%2d: %s, ", i, p->val.str);
remain -= DIST(p->index, prev->index) + 1;
total += p->rate * remain;
printf("dist=%d remain=%d total=%d", DIST(p->index, prev->index), remain,
total);
printf("\n");
i++;
prev = p;
}
}
}
static int doit(int part)
{
struct worker w[2];
struct valve *best;
int res = 0;
//int topick = part == 1? 7: 12;
int topick = part == 1? 12: 12;
w[0].pos = w[1].pos = graph.aa;
//w[0].depth = w[1].depth = part == 1? 7: 4;
w[0].depth = w[1].depth = part == 1? 4: 4;
w[0].time = w[1].time = part == 1? 30: 26;
while ((best = eval(0, part, w, topick, 0))) {
list_del(&best->flow_sorted);
list_add_tail(&best->played, &graph.played[best->worker]);
w[best->worker].time -= DIST(w[best->worker].pos->index, best->index) + 1;
w[best->worker].pos = best;
res += best->rate * w[best->worker].time;
print_played(part);
}
return res;
}
static ulong part1()
{
return doit(1);
}
static ulong part2()
{
return doit(2);
}
int main(int ac, char **av)
{
int part = parseargs(ac, av);
pool_valve = pool_create("valve", 512, sizeof(struct valve));
parse();
build_distances();
print_valves();
printf("%s: res=%lu\n", *av, part == 1? part1(): part2());
exit(0);
}
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