[2022][day 20] add solution

2022/AOC20.py

@@ -0,0 +1,89 @@
+from typing import List
+
+from _utils import read_input, timer, Solution
+
+DECRYPTION_KEY = 811589153
+
+
+class Node:
+ def __init__(self, val: int, prev: "Node" = None, next: "Node" = None):
+ self.val = val
+ self.prev = prev
+ self.next = next
+
+ def __repr__(self):
+ return f"Node({self.val}, prev={self.prev.val}, next={self.next.val})"
+
+
+def process_input(filename: str, decrypt_key: bool) -> List[Node]:
+ _input = read_input(filename)
+ if decrypt_key:
+ _input = [Node(int(val) * DECRYPTION_KEY) for val in _input]
+ else:
+ _input = [Node(int(val)) for val in _input]
+
+ for i, node in enumerate(_input):
+ _input[i].prev = _input[(i - 1) % len(_input)]
+ _input[i].next = _input[(i + 1) % len(_input)]
+ return _input
+
+
+def mix_file(_input: List[Node]) -> List[Node]:
+ n_nodes = len(_input)
+
+ for i in range(n_nodes):
+ node = _input[i]
+ if node.val == 0:
+ continue
+
+ node.prev.next, node.next.prev = node.next, node.prev # remove node
+ new_prev_node, new_next_node = node.prev, node.next
+
+ move = node.val % (n_nodes - 1)
+ for _ in range(move):
+ new_prev_node = new_prev_node.next
+ new_next_node = new_next_node.next
+
+ node.prev, node.next = new_prev_node, new_next_node # update node pointers
+ new_prev_node.next, new_next_node.prev = node, node
+ return _input
+
+
+def grove_coordinates(nodes: List[Node]) -> int:
+ node = nodes[0]
+ while node.val != 0:
+ node = node.next
+
+ solution = 0
+ for i in range(3_000 + 1):
+ if i in (1_000, 2_000, 3_000):
+ solution += node.val
+ node = node.next
+
+ return solution
+
+
+def part1(filename: str) -> int:
+ nodes = process_input(filename, decrypt_key=False)
+ nodes = mix_file(nodes)
+ return grove_coordinates(nodes)
+
+
+def part2(filename: str) -> int:
+ nodes = process_input(filename, decrypt_key=True)
+ for i in range(10):
+ nodes = mix_file(nodes)
+ return grove_coordinates(nodes)
+
+
+@timer
+def main(filename: str) -> Solution:
+ part_1_solution = part1(filename)
+ part_2_solution = part2(filename)
+ return part_1_solution, part_2_solution
+
+
+if __name__ == "__main__":
+ part_1_solution, part_2_solution = main("aoc20.txt")
+ print(f"PART 1: {part_1_solution}") # 19070
+ print(f"PART 2: {part_2_solution}") # 14773357352059

2022/README.md

@@ -21,4 +21,5 @@ This repository contains Python solutions to the 2022 edition of [Advent of Code
 | [16](https://adventofcode.com/2022/day/16) | **Proboscidea Volcanium** | [:star::star:](https://github.com/IAjimi/AdventOfCode/blob/master/2022/AOC16.py) | 
 | [17](https://adventofcode.com/2022/day/17) | **Pyroclastic Flow**: Tetris emulator | [:star:](https://github.com/IAjimi/AdventOfCode/blob/master/2022/AOC17.py) | 
 | [18](https://adventofcode.com/2022/day/18) | **Boiling Boulders**: Exploring 3D grid | [:star::star:](https://github.com/IAjimi/AdventOfCode/blob/master/2022/AOC18.py) | 
-| [19](https://adventofcode.com/2022/day/19) | **Not Enough Minerals** | [:star:](https://github.com/IAjimi/AdventOfCode/blob/master/2022/AOC19.py) | 
+| [19](https://adventofcode.com/2022/day/19) | **Not Enough Minerals** | [:star::star:](https://github.com/IAjimi/AdventOfCode/blob/master/2022/AOC19.py) | 
+| [20](https://adventofcode.com/2022/day/20) | **Grove Positioning System** | [:star::star:](https://github.com/IAjimi/AdventOfCode/blob/master/2022/AOC20.py) |