feat: 2024 day 16

Author: Programator2

2024/16a.py

@@ -0,0 +1,88 @@
+from aoc import *
+from collections import defaultdict
+from functools import reduce
+import pickle
+from pprint import pprint as pp
+import sys
+
+
+DIRS = ((-1, 0), (0, 1), (1, 0), (0, -1))
+
+# 0 1 2 3
+# N E S W
+
+
+def search(m, i, j, face, score, scorem, prev, fro):
+    if (i, j, face) not in scorem:
+        scorem[i, j, face] = score
+        prev[i, j, face] = {fro}
+        if m[i, j] == 'E':
+            return
+    elif scorem[i, j, face] < score:
+        return
+    elif scorem[i, j, face] == score:
+        prev[i, j, face].add(fro)
+        return
+    else:
+        scorem[i, j, face] = score
+        prev[i, j, face] = {fro}
+        if m[i, j] == 'E':
+            return
+    for dir, diff in enumerate(DIRS):
+        newpos = (i + diff[0], j + diff[1])
+        if m.get(newpos, None) in '.E':
+            facediff = abs(face - dir)
+            if facediff == 3:
+                facediff = 1
+            search(
+                m,
+                *newpos,
+                dir,
+                score + 1 + facediff * 1000,
+                scorem,
+                prev,
+                (i, j, face),
+            )
+
+
+def dfs(prev, elem: set):
+    if not elem:
+        return elem
+    return (
+        reduce(
+            lambda x, y: x | y, (dfs(prev, prev.get(e, set())) for e in elem)
+        )
+        | elem
+    )
+
+
+def main(infi: str):
+    sys.setrecursionlimit(100000)
+    inp = load_map_dd(infi)
+    pos = [(i, j) for (i, j), e in inp.items() if e == 'S'][0]
+    face = 1
+    score = {}
+    # store the previous position for state i, j, face -> set(previous states)
+    prev = defaultdict(set)
+    end = [(i, j) for (i, j), e in inp.items() if e == 'E'][0]
+    # print(list((*end, face, score[(*end, face)]) for face in range(4)))
+    # try:
+    #     with open('16.pickle', 'rb') as f:
+    #         prev = pickle.load(f)
+    # except OSError:
+    search(inp, *pos, face, 0, score, prev, None)
+    #     with open('16.pickle', 'wb') as f:
+    #         pickle.dump(prev, f)
+    best_paths = dfs(prev, {(1, 139, 1)})
+    best_paths.remove(None)
+    return len(set((i, j) for i, j, _ in best_paths))
+
+
+DAY = 16
+FILE_TEST = f"{DAY}_testa.txt"
+FILE_TEST = f"{DAY}_testb.txt"
+FILE_EXP = f"{DAY}_exp.txt"
+FILE = f"{DAY}.txt"
+# test_and_submit(main, FILE_TEST, FILE_EXP, FILE, DAY)
+# print(main(FILE_TEST))
+print(main(FILE))

2024/16b.py

@@ -0,0 +1,96 @@
+from aoc import *
+from itertools import (
+    pairwise,
+    combinations,
+    repeat,
+    product,
+    accumulate,
+    permutations,
+    cycle,
+    combinations_with_replacement,
+)
+from more_itertools import (
+    first_true,
+    flatten,
+    ncycles,
+    first_true,
+    zip_broadcast,
+    windowed,
+    chunked,
+    take,
+    peekable,
+)
+import re
+from blessed import BlessedList
+from collections import (
+    namedtuple,
+    defaultdict,
+    OrderedDict,
+    Counter,
+    deque,
+    UserList,
+)
+import operator
+from operator import itemgetter
+from bisect import *
+from functools import reduce, cache, cmp_to_key
+import math
+from copy import deepcopy
+from math import ceil
+from heapq import *
+import sys
+from pprint import pprint as pp
+from statistics import mode
+from string import ascii_uppercase
+
+
+DIRS = ((-1, 0), (0, 1), (1, 0), (0, -1))
+
+# 0 1 2 3
+# N E S W
+
+
+# TODO: Very inefficient. I have to rewrite it using Dijkstra.
+def search(m, i, j, face, score, scorem):
+    if (i, j, face) not in scorem:
+        scorem[i, j, face] = score
+    elif scorem[i, j, face] <= score:
+        return
+    else:
+        scorem[i, j, face] = score
+        if m[i, j] == 'E':
+            return
+    for dir, diff in enumerate(DIRS):
+        newpos = (i + diff[0], j + diff[1])
+        if m.get(newpos, None) in '.E':
+            facediff = abs(face - dir)
+            if facediff == 3:
+                facediff = 1
+            search(m, *newpos, dir, score + 1 + facediff * 1000, scorem)
+
+
+def main(infi: str):
+    sys.setrecursionlimit(100000)
+    inp = load_map_dd(infi)
+    pos = [(i, j) for (i, j), e in inp.items() if e == 'S'][0]
+    face = 1
+    score = {}
+    search(inp, *pos, face, 0, score)
+    end = [(i, j) for (i, j), e in inp.items() if e == 'E'][0]
+    return min(
+        x[3]
+        for x in list(
+            (*end, face, score.get((*end, face), None)) for face in range(4)
+        )
+        if x[3] is not None
+    )
+
+
+DAY = 16
+FILE_TEST = f"{DAY}_testa.txt"
+FILE_TEST = f"{DAY}_testb.txt"
+FILE_EXP = f"{DAY}_exp.txt"
+FILE = f"{DAY}.txt"
+# test_and_submit(main, FILE_TEST, FILE_EXP, FILE, DAY)
+# print(main(FILE_TEST))
+print(main(FILE))

README.org

@@ -13,6 +13,7 @@
 |  19 | 01:44:22 |  6641 |     0 | 01:50:06 |  5444 |     0 |
 |  18 | 00:23:32 |  2771 |     0 | 00:29:19 |  2300 |     0 |
 |  17 | 00:27:08 |  1748 |     0 | 07:06:10 |  5688 |     0 |
+|  16 |     >24h | 24642 |     0 |     >24h | 20241 |     0 |
 |  15 | 00:32:17 |  2397 |     0 | 02:59:49 |  4379 |     0 |
 |  14 | 00:19:09 |  1902 |     0 | 01:13:46 |  3551 |     0 |
 |  13 | 00:39:23 |  4308 |     0 | 12:34:52 | 21706 |     0 |