Validity fluidity

aoc2020/day02/solution.py

@@ -16,20 +16,23 @@ def main() -> int:
 
 
 class Policy:
-    def __init__(self, char: str, min_count: int, max_count: int):
+    def __init__(self, char: str, pos1: int, pos2: int):
         self.char = char
-        self.min_count = min_count
+        self.pos1 = pos1
-        self.max_count = max_count
+        self.pos2 = pos2
 
     @classmethod
     def fromstring(cls, input_string) -> "Policy":
         parts = [s.strip() for s in input_string.split(" ")][:2]
-        min_max = [int(s) for s in parts[0].split("-")][:2]
+        pos = [int(s) for s in parts[0].split("-")][:2]
-        return cls(parts[1], min_max[0], min_max[1])
+        return cls(parts[1], pos[0], pos[1])
 
     def is_valid(self, password: str) -> bool:
-        actual = password.count(self.char)
+        matches = 0
-        return actual >= self.min_count and actual <= self.max_count
+        for pos in (self.pos1 - 1, self.pos2 - 1):
+            if password[pos] == self.char:
+                matches += 1
+        return matches == 1
 
 
 class PolicyPassword: