Solve day 5

05/puzzle.py

@@ -0,0 +1,82 @@
+from itertools import count
+from math import inf
+from typing import Iterable, NamedTuple
+
+
+class RangeConversion(NamedTuple):
+    destination_start: int
+    source_start: int
+    range_length: int
+
+    def resolve(self, source: int) -> int | None:
+        if self.source_start <= source < self.source_start + self.range_length:
+            return self.destination_start + source - self.source_start
+        return None
+
+    def reverse_resolve(self, destination: int) -> int | None:
+        if (
+            self.destination_start
+            <= destination
+            < self.destination_start + self.range_length
+        ):
+            return self.source_start + destination - self.destination_start
+        return None
+
+
+class SeedRange(NamedTuple):
+    start: int
+    length: int
+
+    def includes(self, seed: int):
+        return self.start <= seed < self.start + self.length
+
+
+def resolve_destination(source: int, map: list[RangeConversion]) -> int:
+    for range_conversion in map:
+        if destination := range_conversion.resolve(source):
+            return destination
+    return source
+
+
+def resolve_source(destination: int, map: list[RangeConversion]) -> int:
+    for range_conversion in map:
+        if source := range_conversion.reverse_resolve(destination):
+            return source
+    return destination
+
+
+def solve_pt_1(seeds: list[int], maps: list[list[RangeConversion]]) -> int:
+    minimum_location = 9_999_999_999_999
+    for seed in seeds:
+        result = seed
+        for map in maps:
+            result = resolve_destination(result, map)
+        minimum_location = min(minimum_location, result)
+    return minimum_location
+
+
+def solve_pt_2(seeds: list[int], maps: list[list[RangeConversion]]) -> int:
+    seed_ranges = [
+        SeedRange(start, length) for start, length in zip(seeds[::2], seeds[1::2])
+    ]
+
+    for location in count():
+        if location % 100_000 == 0:
+            print(
+                f"Part 2 - [checking {location:,} through {location + 99_999:,}]",
+                end="\r",
+            )
+
+        result = location
+        for map in reversed(maps):
+            result = resolve_source(result, map)
+
+        seed_candidate = result
+        for map in maps:
+            result = resolve_destination(result, map)
+
+        for seed_range in seed_ranges:
+            if seed_range.includes(seed_candidate):
+                return location
+
+    raise NotImplementedError()