2023: d05: ex1: add solution

2023/d05/ex1/ex1.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python
+
+import sys
+from typing import NamedTuple
+
+
+class AlmanacMapLine(NamedTuple):
+    dest_start: int
+    source_start: int
+    map_len: int
+
+
+class AlmanacMap(NamedTuple):
+    lines: list[AlmanacMapLine]
+
+    def map(self, input: int) -> int:
+        for l in self.lines:
+            if input < l.source_start:
+                continue
+            if (l.source_start + l.map_len) <= input:
+                continue
+            return l.dest_start + (input - l.source_start)
+        return input
+
+
+Almanac = dict[str, tuple[str, AlmanacMap]]
+
+
+def solve(input: str) -> int:
+    def parse_almanac_map_line(line: str) -> AlmanacMapLine:
+        dest_start, source_start, map_len = map(int, line.split(" "))
+        return AlmanacMapLine(dest_start, source_start, map_len)
+
+    def parse_almanac_map(lines: list[str]) -> tuple[str, str, AlmanacMap]:
+        source, dest = lines[0].split(" ")[0].split("-")[::2]
+
+        map_lines = [parse_almanac_map_line(line) for line in lines[1:]]
+
+        return source, dest, AlmanacMap(map_lines)
+
+    def parse_almanac(paragraphs: list[str]) -> Almanac:
+        res: Almanac = {}
+
+        for raw_map in paragraphs:
+            source, dest, map = parse_almanac_map(raw_map.splitlines())
+            res[source] = dest, map
+
+        return res
+
+    def parse(input: str) -> tuple[set[int], Almanac]:
+        raw_seeds, *raw_almanac = input.split("\n\n")
+
+        seeds = set(int(n) for n in raw_seeds.removeprefix("seeds: ").split(" "))
+
+        return seeds, parse_almanac(raw_almanac)
+
+    def to_dest(almanac: Almanac, input: int, input_type: str, dest_type: str) -> int:
+        if input_type == dest_type:
+            return input
+        new_input_type, map = almanac[input_type]
+        return to_dest(almanac, map.map(input), new_input_type, dest_type)
+
+    seeds, almanac = parse(input)
+    return min(to_dest(almanac, seed, "seed", "location") for seed in seeds)
+
+
+def main() -> None:
+    input = sys.stdin.read()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()