Start day 20.

2022/day20.py

@@ -0,0 +1,104 @@
+# -*- encoding: utf-8 -*-
+
+import math
+import sys
+
+
+class Number:
+    processed: bool
+    value: int
+
+    def __init__(self, value: int):
+        self.value = value
+        self.processed = False
+
+    def __eq__(self, other):
+        if isinstance(other, Number):
+            return self.value == other.value
+        elif isinstance(other, int):
+            return self.value == other
+        return False
+
+    def __str__(self):
+        return str(self.value)
+
+    def __repr__(self):
+        return str(self)
+
+
+expected = iter(
+    [
+        [1, 2, -3, 3, -2, 0, 4],
+        [2, 1, -3, 3, -2, 0, 4],
+        [1, -3, 2, 3, -2, 0, 4],
+        [1, 2, 3, -2, -3, 0, 4],
+        [1, 2, -2, -3, 0, 3, 4],
+        [1, 2, -3, 0, 3, 4, -2],
+        [1, 2, -3, 0, 3, 4, -2],
+        [1, 2, -3, 4, 0, 3, -2],
+    ]
+)
+
+
+numbers = [Number(int(x)) for x in sys.stdin.readlines()]
+# numbers = [Number(0), Number(0), Number(-6)]
+
+# print(next(expected))
+# print(numbers)
+# print("---")
+
+index = 0
+while index < len(numbers):
+    if numbers[index].processed:
+        index += 1
+        continue
+
+    number = numbers[index]
+    number.processed = True
+    target = (
+        index
+        + (number.value % len(numbers))
+        - int(number.value < 0) * math.ceil(abs(number.value) / len(numbers))
+    ) % len(numbers)
+
+    # print(
+    #     f"moving {number} from {index} to {target} (between {numbers[target]} and {numbers[(target + 1) % len(numbers)]})"
+    # )
+    if target == index:
+        index += 1
+    elif target == index + 1:
+        numbers[index], numbers[target] = numbers[target], numbers[index]
+    elif target == index - 1:
+        numbers[index], numbers[target] = numbers[target], numbers[index]
+    elif target > index:
+        # print(
+        #     numbers[:index],
+        #     numbers[index + 1 : target + 1],
+        #     [numbers[index]],
+        #     numbers[target + 1 :],
+        # )
+        numbers = (
+            numbers[:index]
+            + numbers[index + 1 : target + 1]
+            + [numbers[index]]
+            + numbers[target + 1 :]
+        )
+    else:
+        numbers = (
+            numbers[: target + 1]
+            + [numbers[index]]
+            + numbers[target + 1 : index]
+            + numbers[index + 1 :]
+        )
+        index -= 1
+
+    # print(next(expected))
+    # print(numbers)
+    # print("---")
+
+index_of_0 = numbers.index(Number(0))
+
+answer_1 = sum(
+    numbers[(index_of_0 + offset) % len(numbers)].value for offset in (1000, 2000, 3000)
+)
+print(f"answer 1 is {answer_1}")

2022/tests/day20.txt

@@ -0,0 +1,7 @@
+1
+2
+-3
+3
+-2
+0
+4