day 15 part 1
This commit is contained in:
@@ -33,3 +33,130 @@ Your goal is to find a path with the lowest total risk. In this example, a path
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The total risk of this path is 40 (the starting position is never entered, so its risk is not counted).
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What is the lowest total risk of any path from the top left to the bottom right?
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Your puzzle answer was 435.
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The first half of this puzzle is complete! It provides one gold star: *
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--- Part Two ---
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Now that you know how to find low-risk paths in the cave, you can try to find your way out.
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The entire cave is actually five times larger in both dimensions than you thought; the area you originally scanned is just one tile in a 5x5 tile area that forms the full map. Your original map tile repeats to the right and downward; each time the tile repeats to the right or downward, all of its risk levels are 1 higher than the tile immediately up or left of it. However, risk levels above 9 wrap back around to 1. So, if your original map had some position with a risk level of 8, then that same position on each of the 25 total tiles would be as follows:
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8 9 1 2 3
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9 1 2 3 4
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1 2 3 4 5
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2 3 4 5 6
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3 4 5 6 7
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Each single digit above corresponds to the example position with a value of 8 on the top-left tile. Because the full map is actually five times larger in both dimensions, that position appears a total of 25 times, once in each duplicated tile, with the values shown above.
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Here is the full five-times-as-large version of the first example above, with the original map in the top left corner highlighted:
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11637517422274862853338597396444961841755517295286
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13813736722492484783351359589446246169155735727126
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21365113283247622439435873354154698446526571955763
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36949315694715142671582625378269373648937148475914
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74634171118574528222968563933317967414442817852555
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13191281372421239248353234135946434524615754563572
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13599124212461123532357223464346833457545794456865
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31254216394236532741534764385264587549637569865174
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12931385212314249632342535174345364628545647573965
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23119445813422155692453326671356443778246755488935
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22748628533385973964449618417555172952866628316397
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24924847833513595894462461691557357271266846838237
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32476224394358733541546984465265719557637682166874
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47151426715826253782693736489371484759148259586125
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85745282229685639333179674144428178525553928963666
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24212392483532341359464345246157545635726865674683
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24611235323572234643468334575457944568656815567976
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42365327415347643852645875496375698651748671976285
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23142496323425351743453646285456475739656758684176
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34221556924533266713564437782467554889357866599146
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33859739644496184175551729528666283163977739427418
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35135958944624616915573572712668468382377957949348
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43587335415469844652657195576376821668748793277985
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58262537826937364893714847591482595861259361697236
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96856393331796741444281785255539289636664139174777
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35323413594643452461575456357268656746837976785794
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35722346434683345754579445686568155679767926678187
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53476438526458754963756986517486719762859782187396
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34253517434536462854564757396567586841767869795287
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45332667135644377824675548893578665991468977611257
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44961841755517295286662831639777394274188841538529
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46246169155735727126684683823779579493488168151459
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54698446526571955763768216687487932779859814388196
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69373648937148475914825958612593616972361472718347
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17967414442817852555392896366641391747775241285888
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46434524615754563572686567468379767857948187896815
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46833457545794456865681556797679266781878137789298
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64587549637569865174867197628597821873961893298417
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45364628545647573965675868417678697952878971816398
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56443778246755488935786659914689776112579188722368
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55172952866628316397773942741888415385299952649631
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57357271266846838237795794934881681514599279262561
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65719557637682166874879327798598143881961925499217
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71484759148259586125936169723614727183472583829458
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28178525553928963666413917477752412858886352396999
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57545635726865674683797678579481878968159298917926
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57944568656815567976792667818781377892989248891319
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75698651748671976285978218739618932984172914319528
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56475739656758684176786979528789718163989182927419
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67554889357866599146897761125791887223681299833479
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Equipped with the full map, you can now find a path from the top left corner to the bottom right corner with the lowest total risk:
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11637517422274862853338597396444961841755517295286
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13813736722492484783351359589446246169155735727126
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21365113283247622439435873354154698446526571955763
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36949315694715142671582625378269373648937148475914
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74634171118574528222968563933317967414442817852555
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13191281372421239248353234135946434524615754563572
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13599124212461123532357223464346833457545794456865
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31254216394236532741534764385264587549637569865174
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12931385212314249632342535174345364628545647573965
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23119445813422155692453326671356443778246755488935
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22748628533385973964449618417555172952866628316397
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24924847833513595894462461691557357271266846838237
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32476224394358733541546984465265719557637682166874
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47151426715826253782693736489371484759148259586125
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85745282229685639333179674144428178525553928963666
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24212392483532341359464345246157545635726865674683
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24611235323572234643468334575457944568656815567976
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42365327415347643852645875496375698651748671976285
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23142496323425351743453646285456475739656758684176
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34221556924533266713564437782467554889357866599146
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33859739644496184175551729528666283163977739427418
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35135958944624616915573572712668468382377957949348
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43587335415469844652657195576376821668748793277985
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58262537826937364893714847591482595861259361697236
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96856393331796741444281785255539289636664139174777
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35323413594643452461575456357268656746837976785794
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35722346434683345754579445686568155679767926678187
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53476438526458754963756986517486719762859782187396
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34253517434536462854564757396567586841767869795287
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45332667135644377824675548893578665991468977611257
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44961841755517295286662831639777394274188841538529
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46246169155735727126684683823779579493488168151459
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54698446526571955763768216687487932779859814388196
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69373648937148475914825958612593616972361472718347
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17967414442817852555392896366641391747775241285888
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46434524615754563572686567468379767857948187896815
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46833457545794456865681556797679266781878137789298
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64587549637569865174867197628597821873961893298417
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45364628545647573965675868417678697952878971816398
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56443778246755488935786659914689776112579188722368
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55172952866628316397773942741888415385299952649631
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57357271266846838237795794934881681514599279262561
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65719557637682166874879327798598143881961925499217
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71484759148259586125936169723614727183472583829458
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28178525553928963666413917477752412858886352396999
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57545635726865674683797678579481878968159298917926
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57944568656815567976792667818781377892989248891319
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75698651748671976285978218739618932984172914319528
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56475739656758684176786979528789718163989182927419
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67554889357866599146897761125791887223681299833479
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The total risk of this path is 315 (the starting position is still never entered, so its risk is not counted).
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Using the full map, what is the lowest total risk of any path from the top left to the bottom right?
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219
2021/day15/aoc-c.c
Normal file
219
2021/day15/aoc-c.c
Normal file
@@ -0,0 +1,219 @@
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/* aoc-c.c: Advent of Code 2021, day 15 parts 1 & 2
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*
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* Copyright (C) 2021 Bruno Raoult ("br")
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* Licensed under the GNU General Public License v3.0 or later.
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* Some rights reserved. See COPYING.
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*
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* You should have received a copy of the GNU General Public License along with this
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* program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
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*
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* SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <malloc.h>
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#include <ctype.h>
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#include <stdint.h>
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#include "debug.h"
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#include "pool.h"
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#include "bits.h"
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#include "list.h"
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#define MAX_SIZE 128
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int a[] = {
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['a'] = 0,
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['b'] = 1,
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['c'] = 2
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};
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typedef struct square {
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uchar cost;
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u32 totcost;;
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uchar visited;
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} square_t;
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typedef struct priority_queue {
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int l;
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int c;
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u32 cost;
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struct list_head list;
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} pqueue_t;
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static LIST_HEAD(plist_head);
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static struct square array[MAX_SIZE][MAX_SIZE];
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static int asize;
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static pool_t *pool;
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#define VALID(x, y) ((x) >= 0 && (x) < size && (y) >= 0 && (y) < size )
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static void print_array()
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{
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log(3, "array (%dx%d):\n", asize, asize);
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for (int i = 0; i < asize; ++i) {
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for (int j = 0; j < asize; ++j)
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log(3, "%1d/%2d ", array[i][j].cost, array[i][j].totcost);
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log(3, "\n");
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}
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}
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static void print_queue()
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{
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log(3, "queue:\n", asize, asize);
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pqueue_t *tmp;
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int i = 1;
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list_for_each_entry(tmp, &plist_head, list) {
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int l = tmp->l, c = tmp->c;
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u32 cost = array[l][c].cost;
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u32 acc = array[l][c].totcost;
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log(3, "%d: (%d,%d): cost=%u acc=%lu\n", i, l, c, cost, acc);
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i++;
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}
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}
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/* insert l,c in queue, keeping cost sorted */
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static pqueue_t *push(int l, int c, u32 parentcost)
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{
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pqueue_t *queue;
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u32 newcost;
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if (l >= asize || c >= asize || array[l][c].visited)
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return NULL;
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newcost = parentcost + array[l][c].cost;
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if (newcost > array[l][c].totcost)
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return NULL;
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queue = pool_get(pool);
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queue->l = l;
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queue->c = c;
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queue->cost = newcost;
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array[l][c].totcost = newcost;
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log_f(3, "(%d,%d) pcost=%u\n", l, c, newcost);
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list_add_tail(&queue->list, &plist_head);
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return queue;
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}
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static pqueue_t *pop()
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{
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pqueue_t *tmp, *cur;
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list_for_each_entry_safe(cur, tmp, &plist_head, list) {
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int l = cur->l, c = cur->c;
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list_del(&cur->list);
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if (array[l][c].visited) {
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pool_add(pool, cur);
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continue;
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}
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log_f(3, "(%d,%d) cost=%u\n", l, c, array[l][c].totcost);
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return cur;
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}
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return NULL;
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}
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/* read data and create graph.
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*/
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static int read_input()
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{
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size_t alloc = 0;
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char *buf;
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ssize_t len;
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int l = 0, c;
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/* get points list */
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while ((len = getline(&buf, &alloc, stdin)) > 0) {
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buf[--len] = 0;
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//printf("%d: size=%d [%s]\n", l, asize, buf);
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for (c = 0; buf[c]; ++c) {
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array[l][c].cost = buf[c] - '0';
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array[l][c].totcost = UINT32_MAX;
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array[l][c].visited = 0;
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}
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l++;
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}
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free(buf);
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asize = l;
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//print_array();
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return asize;
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}
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static u32 part1()
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{
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pqueue_t *pqueue;
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u32 best = UINT32_MAX;
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push(0, 0, 0);
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while ((pqueue = pop())) {
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int l = pqueue->l, c = pqueue->c;
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u32 acc = array[l][c].totcost;
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if (l == (asize - 1) && c == (asize - 1)) {
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if (acc < best) {
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best = acc;
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log_f(3, "New best: %u\n", best);
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}
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}
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push(l, c + 1, acc);
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push(l + 1, c, acc);
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array[l][c].visited = 1;
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pool_add(pool, pqueue); /* recycle pqueue in memory pool */
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}
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/* as we accounted [0][0] cost, we must substract it */
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return best - array[0][0].cost;
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}
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static u32 part2()
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{
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return 2;
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}
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static u32 doit(int part)
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{
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read_input();
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return part == 1? part1(): part2();
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}
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static int usage(char *prg)
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{
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fprintf(stderr, "Usage: %s [-d debug_level] [-p part]\n", prg);
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return 1;
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}
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int main(int ac, char **av)
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{
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int opt, part = 1;
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while ((opt = getopt(ac, av, "d:p:")) != -1) {
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switch (opt) {
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case 'd':
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debug_level_set(atoi(optarg));
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break;
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case 'p': /* 1 or 2 */
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part = atoi(optarg);
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if (part < 1 || part > 2)
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return usage(*av);
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break;
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default:
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return usage(*av);
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}
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}
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if (optind < ac)
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return usage(*av);
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if (!(pool = pool_init("stack", 1024, sizeof (pqueue_t))))
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return -1;
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printf("%s : res=%d\n", *av, doit(part));
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exit (0);
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}
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Reference in New Issue
Block a user