2024 day 1

Author: sanderploegsma

2024/python/day01.py

@@ -0,0 +1,55 @@
+"""
+Advent of Code 2024, Day 1: Historian Hysteria.
+
+See: https://adventofcode.com/2024/day/1
+"""
+
+import sys
+from collections import defaultdict
+from typing import TextIO
+
+
+def part_one(file: TextIO) -> int:
+    """
+    Solve part one of the puzzle.
+    """
+    left, right = [], []
+    for line in file.readlines():
+        a, b = line.split(maxsplit=1)
+        left.append(int(a))
+        right.append(int(b))
+
+    left, right = sorted(left), sorted(right)
+
+    return sum(map(lambda n: abs(n[0] - n[1]), zip(left, right)))
+
+
+def part_two(file: TextIO) -> int:
+    """
+    Solve part two of the puzzle.
+    """
+    left, right = [], defaultdict(lambda: 0)
+
+    for line in file.readlines():
+        a, b = line.split(maxsplit=1)
+        left.append(int(a))
+        right[int(b)] += 1
+
+    return sum(map(lambda n: n * right[n], left))
+
+
+def main():
+    """
+    The main entrypoint for the script.
+    """
+    filename = sys.argv[0].replace(".py", ".txt")
+
+    with open(filename, encoding="utf-8") as file:
+        print("Part one:", part_one(file))
+
+    with open(filename, encoding="utf-8") as file:
+        print("Part two:", part_two(file))
+
+
+if __name__ == "__main__":
+    main()