2022 day3

Author: dwj300

2022/3.py

@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+import re
+import sys
+
+def score_item(item):
+    if ord(item) >= ord('a') and ord(item) <= ord('z'):
+        return ord(item) - ord('a') + 1
+    return ord(item) - ord('A') + 27
+
+def part1(lines): 
+    def compute(line):
+        n = len(line)
+        p1, p2 = line[:(n//2)], line[(n//2):]
+        items = set(p1).intersection(set(p2))
+        return score_item(list(items)[0])
+    return sum(map(compute, lines))
+
+def part2(lines):
+    i, s = 0, 0
+    while i < len(lines):
+        items = set(lines[i])
+        for j in range(2):
+            items.intersection_update(lines[i+1+j])
+        s += score_item(list(items)[0])
+        i += 3
+    return s
+
+if __name__ == "__main__":
+    day = re.match("(?:./)?([0-9]+).py", sys.argv[0]).groups()[0]
+    filename = sys.argv[1] if len(sys.argv) > 1 else f"{day}.txt"
+    lines = open(filename).read().strip().split('\n')
+    print(part1(lines))
+    print(part2(lines))