Completed part 1 of day 20 of year 2024

Author: fschatbot

2024/20.py

@@ -0,0 +1,76 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+def parse(data):
+	grid = []
+	boundX, boundY = len(data.split('\n')[0]), len(data.split('\n'))
+	start = None, None
+	end = None, None
+	for y, line in enumerate(data.split('\n')):
+		for x, char in enumerate(line):
+			if char == '#':
+				grid.append((x, y))
+			elif char == '.':
+				pass
+			elif char == 'S':
+				start = x, y
+			elif char == 'E':
+				end = x, y
+	
+	return grid, (boundX, boundY), start, end
+
+split_data = parse
+completed = 1
+raw_data = None # Not To be touched
+
+def pathFinder(grid, start, end):
+	# Simple greedy algo since there is only one path
+	path = [start, start]
+	directions = [(0, -1), (0, 1), (1, 0), (-1, 0)]
+	while path[-1] != end:
+		# print(path[-1])
+		for dx, dy in directions:
+			nx, ny = path[-1][0]+dx, path[-1][1]+dy
+			if (nx, ny) in grid: continue
+			if (nx, ny) == path[-2]: continue
+
+			path.append((nx, ny))
+			break
+	
+	return path[1:]
+
+
+def part1(data):
+	grid, bounds, start, end = data
+	path = pathFinder(grid, start, end)
+
+	moves = [(0, -2), (0, 2), (2, 0), (-2, 0)]
+
+	counter = 0
+
+	for i, (x, y) in enumerate(path):
+		for dx, dy in moves:
+			nx, ny = x + dx, y + dy
+			if (nx, ny) not in path[i:]: continue
+			save = path[i:].index((nx, ny)) - 2
+			if save >= 100: counter += 1
+	
+	return counter
+
+def part2(data):
+	grid, bounds, start, end = data
+	path = pathFinder(grid, start, end)
+
+	# Some black magic is required over here cause the amount of checks look like 10k * 50**2 ~= 25 mill
+	moves = [(0, -2), (0, 2), (2, 0), (-2, 0)]
+
+	counter = 0
+
+	for i, (x, y) in enumerate(path):
+		for dx, dy in moves:
+			nx, ny = x + dx, y + dy
+			if (nx, ny) not in path[i:]: continue
+			save = path[i:].index((nx, ny)) - 2
+			if save >= 100: counter += 1
+	
+	return counter