python regex

2024/day03/day03.py

@@ -0,0 +1,43 @@
+import re
+
+
+def part1(input: str) -> int:
+    matches = re.findall(r"mul\(\d+,\d+\)", input)
+    ans = 0
+    for match in matches:
+        ans += exec_mul(match)
+    return ans
+
+
+def part2(input: str) -> int:
+    matches = re.findall(r"(do\(\)|don\'t\(\)|mul\(\d+,\d+\))", input)
+    do = True
+    ans = 0
+
+    for match in matches:
+        if match == "do()":
+            do = True
+        elif match == "don't()":
+            do = False
+        elif do:
+            ans += exec_mul(match)
+
+    return ans
+
+
+def exec_mul(s: str) -> int:
+    nums = re.findall(r"\d+", s)
+    return int(nums[0]) * int(nums[1])
+
+
+example = "xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))"
+
+print("example part1:", part1(example), "want", 161)
+
+input = open("input.txt").read()
+print("part1:", part1(input), "want", 169021493)
+
+example2 = "xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))"
+
+print("example part2:", part2(example2), "want", 48)
+print("part2:", part2(input), "want", 111762583)