Day 11, 12, 13.

d11.py

@@ -0,0 +1,143 @@
+import re
+from string import ascii_lowercase, ascii_uppercase
+
+def extract_single_digit(line: str) -> int:
+    r = re.compile(r"\d+")
+    for m in r.findall(line):
+        return int(m)
+    raise Exception("No single digit sequence in '{line}'")
+
+def extract_digits_list(line: str) -> list[int]:
+    r = re.compile(r"\d+")
+    return list(map(int, r.findall(line)))
+
+EXAMPLE = """
+Monkey 0:
+  Starting items: 79, 98
+  Operation: new = old * 19
+  Test: divisible by 23
+    If true: throw to monkey 2
+    If false: throw to monkey 3
+
+Monkey 1:
+  Starting items: 54, 65, 75, 74
+  Operation: new = old + 6
+  Test: divisible by 19
+    If true: throw to monkey 2
+    If false: throw to monkey 0
+
+Monkey 2:
+  Starting items: 79, 60, 97
+  Operation: new = old * old
+  Test: divisible by 13
+    If true: throw to monkey 1
+    If false: throw to monkey 3
+
+Monkey 3:
+  Starting items: 74
+  Operation: new = old + 3
+  Test: divisible by 17
+    If true: throw to monkey 0
+    If false: throw to monkey 1
+"""
+
+def clean(text: str) -> list[str]:
+    return list(filter(lambda l: l.strip() != "", text.splitlines()))
+
+def get_monkesy(lines):
+    monkeys = []
+    for i, line in enumerate(lines):
+        if line.startswith("Monkey"):
+            d = extract_single_digit(line)
+            monkeys.append([d])
+        elif line.strip().startswith("Starting"):
+            d = extract_digits_list(line)
+            monkeys[-1].append(d)
+        elif line.strip().startswith("Operation"):
+            if "old * old" in line:
+                f = lambda y: y * y
+                monkeys[-1].append(f)
+            elif "*" in line:
+                d = extract_single_digit(line)
+                f = lambda x: (lambda y: x * y)
+                f = f(d)
+                monkeys[-1].append(f)
+            elif "+" in line:
+                d = extract_single_digit(line)
+                f = lambda x: (lambda y: x + y)
+                f = f(d)
+                monkeys[-1].append(f)
+            else:
+                raise Exception(line)
+        elif line.strip().startswith("Test"):
+            d = extract_single_digit(line)
+            monkeys[-1].append(d)
+        elif line.strip().startswith("If true"):
+            d = extract_single_digit(line)
+            monkeys[-1].append(d)
+        elif line.strip().startswith("If false"):
+            d = extract_single_digit(line)
+            monkeys[-1].append(d)
+        else:
+            print(line)
+            raise Exception("Unexpected line.")
+    for m in monkeys:
+        m.append(0)
+    return monkeys
+
+def solve(lines: list[str]):
+    monkeys = get_monkesy(lines)
+    for _ in range(20):
+        for monkey in monkeys:
+            id, items, op, test, if_true, if_false, count = monkey
+            while items:
+                item = items.pop()
+                monkey[6] += 1
+                worry = item
+                worry = op(worry)
+                worry //= 3
+                if worry % test == 0:
+                    monkeys[if_true][1].append(worry)
+                else:
+                    monkeys[if_false][1].append(worry)
+                monkeys[id][1] = monkeys[id][1][1:]
+    counts = sorted([m[6] for m in monkeys])[-2:]
+    return counts[0] * counts[1]
+
+def solve2(lines: list[str]):
+    monkeys = get_monkesy(lines)
+    mod = 1
+    for m in monkeys:
+        mod *= m[3]
+
+    for _ in range(10000):
+        for monkey in monkeys:
+            id, items, op, test, if_true, if_false, count = monkey
+            for item in list(items):
+                monkey[6] += 1
+                worry = item
+                worry = op(worry)
+                worry %= mod
+                if worry % test == 0:
+                    monkeys[if_true][1].append(worry)
+                else:
+                    monkeys[if_false][1].append(worry)
+                monkeys[id][1] = monkeys[id][1][1:]
+    counts = sorted([m[6] for m in monkeys])[-2:]
+    return counts[0] * counts[1]
+
+def main():
+    example = clean(EXAMPLE)
+    print("Example  1:", solve(example))
+
+    data = clean(open("i11.txt").read())
+    print("Solution 1:", solve(data))
+
+    example = clean(EXAMPLE)
+    print("Example  2:", solve2(example))
+
+    data = clean(open("i11.txt").read())
+    print("Solution 2:", solve2(data))
+
+if __name__ == "__main__":
+    main()