2020: d16: ex1: add solution

2020/d16/ex1/ex1.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python
+import sys
+from typing import Dict, List, Set, Tuple
+
+Ranges = Dict[str, Set[int]]
+Ticket = List[int]
+
+
+def parse(raw: List[str]) -> Tuple[Ranges, List[Ticket]]:
+    def extract_field_info(line: str) -> Tuple[str, Set[int]]:
+        field, rest = line.split(":")
+        ranges: Set[int] = set()
+        for r in rest.strip().split(" or "):
+            lhs, rhs = r.split("-")
+            ranges |= set(range(int(lhs), int(rhs) + 1))
+        return field, ranges
+
+    def parse_tickets(line: str) -> Ticket:
+        return [int(i) for i in line.split(",")]
+
+    ranges: Ranges = {}
+    tickets: List[Ticket] = []
+
+    should_parse_tickets = False
+    for line in raw:
+        if line == "":
+            should_parse_tickets = True
+            continue
+        if "ticket" in line:
+            continue
+        if should_parse_tickets:
+            tickets.append(parse_tickets(line))
+        else:
+            field, field_ranges = extract_field_info(line)
+            ranges[field] = field_ranges
+
+    return ranges, tickets
+
+
+def solve(raw: List[str]) -> int:
+    ranges, tickets = parse(raw)
+    sum = 0
+
+    for ticket in tickets[1:]:
+        for val in ticket:
+            if any(val in r for r in ranges.values()):
+                continue
+            sum += val
+
+    return sum
+
+
+def main() -> None:
+    input = [line.strip() for line in sys.stdin.readlines()]
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()