p10

aoc24/p10.py

@@ -0,0 +1,45 @@
+from aoc24 import utils
+
+
+class Grid(utils.Grid[int]):
+    def sum_trailhead_scores(self, *, by_rating: bool) -> int:
+        trails = [
+            self.count_hiking_trails(c, by_rating=by_rating) for c in self.trailheads()
+        ]
+        return sum(trails)
+
+    def trailheads(self) -> list[utils.Coord]:
+        return [c for c in self if self[c] == 0]
+
+    def count_hiking_trails(self, trailhead: utils.Coord, *, by_rating: bool) -> int:
+        stack = [trailhead]
+        result = 0
+        visited: set[utils.Coord] = set()
+        while stack:
+            c = stack.pop()
+            if not by_rating:
+                if c in visited:
+                    continue
+                visited.add(c)
+            height = self[c]
+            if height == 9:
+                result += 1
+                continue
+            for n in self.cross_neighbors(c):
+                if self[n] == height + 1:
+                    stack.append(n)
+        return result
+
+
+def parse_input(lines: list[str]) -> Grid:
+    return Grid([[int(c) for c in line] for line in lines])
+
+
+def main() -> None:
+    grid = parse_input(utils.read_input_lines(__file__))
+    print(grid.sum_trailhead_scores(by_rating=False))
+    print(grid.sum_trailhead_scores(by_rating=True))
+
+
+if __name__ == "__main__":
+    main()

data/p10.txt

@@ -0,0 +1,47 @@
+78434565658934341239890154327898789410169567876
+89125676543823430123763267016505654321678478965
+74034389012710569834354108987419783210501329450
+65985293405613478765587017096328798193432010321
+54876102564302349323498723165437689087589876501
+03123001273211058010567654232126575670670345432
+12054320985670769623458912343071464321561210894
+23065011234987878543467801056780352143254308743
+52176020143010987632966532963091243034165789652
+43982176542123676701876547872108389435045630001
+04343987233034565899892101543219474326554321100
+15458980154901454300765413256978365217893033234
+26967898067872343211234322107863210105676128744
+37810587120143443205895013278954306018985439653
+45721456431234556106786784567805217897851058912
+96012367589109667676632397876516986786542367803
+87183398676008768985541098923427875987034456934
+45698432195419878104323567012434564100124325965
+34787563084328769012013432100123473236787619876
+23456976176101098743100169981210984345894500761
+10067885105432345654221058974303876201903121450
+00198793234569854783334567565012565102812034321
+87235630321478345698448987545643476983456965410
+96544321410145430789567496538753985876589876521
+87875401521034521876321323429832104367674307834
+76965432690123670965410210018943011278765212985
+10126501785434987012124567877654780569890156676
+67635652376501456921023498965345698430732347787
+58548743210122357830010329453276582521231298898
+19989834543218766545689414340189891234560106787
+05678129670109658998776504276567760143671015890
+14329078786788347643210543183498452087982384321
+23010879895690210556987652092354301096543493430
+10123965654321987467878941001289212332102584321
+89854434365432176307650030110176565443001675610
+78765601278300045218941121230145896558903498701
+01251012369211234567132430548234787367812345672
+14344323054334565478012986699876572210787434987
+65689454120423672389873677780125601923896523654
+56788763201210981014564578456234892854589018743
+45697899854327872103434569327844763765474329012
+34307656761056932112363231218903454892365215603
+43218947892343341001454120305412178901054508763
+52107232103217654012360019456543065016543459454
+67800134564308567897871298787832104327872106563
+58910129875699430108998345690965432112967654312
+67623456766780123234567654321678987003458901203

tests/test_p10.py

@@ -0,0 +1,31 @@
+from aoc24 import p10
+
+
+def test_example_1() -> None:
+    lines = """
+89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732
+""".strip().splitlines()
+    grid = p10.parse_input(lines)
+    assert grid.sum_trailhead_scores(by_rating=False) == 36
+
+
+def test_example_2() -> None:
+    lines = """
+89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732
+""".strip().splitlines()
+    grid = p10.parse_input(lines)
+    assert grid.sum_trailhead_scores(by_rating=True) == 81