Added day 13 for 2024

2024/src/day13.py

@@ -0,0 +1,126 @@
+import sys
+from inputs import load_input
+
+
+def part1() -> int:
+    input_strings = load_input("./input/day13")
+    problems = parse_problems(input_strings)
+    sum = 0
+    for problem in problems:
+        sum += try_solve_problem(problem)
+    return sum
+
+
+def part2() -> int:
+    input_strings = load_input("./input/day13")
+    problems = parse_problems(input_strings)
+    problems = convert_problems_to_part_2(problems)
+    sum = 0
+    for problem in problems:
+        sum += try_solve_problem(problem, bound_check=False)
+    return sum
+
+
+class Button:
+    def __init__(self, x_move: int, y_move: int) -> None:
+        self.x_move = x_move
+        self.y_move = y_move
+
+    @classmethod
+    def parse_button(cls, input_string: str) -> "Button":
+        numbers = input_string.strip().split(":")[1]
+        number_split = numbers.split(",")
+        x, y = number_split[0].strip().replace("X", ""), number_split[
+            1
+        ].strip().replace("Y", "")
+        return Button(int(x), int(y))
+
+    def __str__(self) -> str:
+        return f"Button({self.x_move}, {self.y_move})"
+
+
+class Problem:
+    def __init__(self, a: Button, b: Button, x_target: int, y_target: int) -> None:
+        self.a = a
+        self.b = b
+        self.x_target = x_target
+        self.y_target = y_target
+
+    @classmethod
+    def parse_problem(cls, a: Button, b: Button, input_string: str) -> "Problem":
+        numbers = input_string.strip().split(":")[1]
+        number_split = numbers.split(",")
+        x, y = number_split[0].strip().replace("X=", ""), number_split[
+            1
+        ].strip().replace("Y=", "")
+        return Problem(a, b, int(x), int(y))
+
+    def __str__(self) -> str:
+        return (
+            f"Problem({str(self.a)}, {str(self.b)}, {self.x_target}, {self.y_target})"
+        )
+
+
+def parse_problems(input_strings: list[str]) -> list[Problem]:
+    result = []
+    a: Button = Button(0, 0)
+    b: Button = Button(0, 0)
+    for each in input_strings:
+        line = each.strip()
+        if line == "":
+            continue
+        else:
+            if "A" in line:
+                a = Button.parse_button(line)
+            elif "B" in line:
+                b = Button.parse_button(line)
+            else:
+                result.append(Problem.parse_problem(a, b, line))
+
+    return result
+
+
+def convert_problems_to_part_2(problems: list[Problem]) -> list[Problem]:
+    for problem in problems:
+        problem.x_target += 10000000000000
+        problem.y_target += 10000000000000
+    return problems
+
+
+def try_solve_problem(problem: Problem, bound_check: bool = True) -> int:
+    # 1: n * x_a + m * x_b = x_target
+    # 2: n * y_a + m * y_b = y_target
+    a = problem.a
+    b = problem.b
+    factor_1 = b.y_move
+    factor_2 = b.x_move
+    if (b.x_move > 0 and b.y_move > 0) or (b.x_move < 0 and b.y_move < 0):
+        factor_2 = -1 * factor_2
+
+    # n = (problem.x_target * factor_1 + problem.y_target * factor_2) / (
+    #     a.x_move * factor_1 + a.y_move * factor_2
+    # )
+    n1 = problem.x_target * factor_1 + problem.y_target * factor_2
+    n2 = a.x_move * factor_1 + a.y_move * factor_2
+    if n1 % n2 != 0:
+        return 0
+    n = n1 // n2
+
+    # m = (problem.x_target - (n * a.x_move)) / b.x_move
+    m1 = problem.x_target - n * a.x_move
+    m2 = b.x_move
+    if m1 % m2 != 0:
+        return 0
+    m = m1 // m2
+
+    result = 0
+    if bound_check:
+        if n <= 100 and m <= 100:
+            result = n * 3 + m
+    else:
+        result = n * 3 + m
+    return result
+
+
+if __name__ == "__main__":
+    print(globals()[sys.argv[1]]())