116 lines
2.7 KiB
Python
116 lines
2.7 KiB
Python
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#!/usr/bin/env python3
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from itertools import count, takewhile
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directions = (
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(-1, -1),
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(-1, 0),
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(-1, 1),
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(0, -1),
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(0, 1),
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(1, -1),
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(1, 0),
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(1, 1),
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)
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grid_width = 98
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grid_height = 97
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def handle_empty(index, grid, next_grid):
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"""
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If a seat is empty (L) and there are no occupied seats adjacent to it, the seat becomes occupied.
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"""
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neighbors = count_neighbors(index, grid)
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if neighbors == 0:
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next_grid[index] = "#"
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return 1
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return 0
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def handle_occupied(index, grid, next_grid):
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"""
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If a seat is occupied (#) and four or more seats adjacent to it are also occupied, the seat becomes empty.
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"""
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neighbors = count_neighbors(index, grid)
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if neighbors >= 4:
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next_grid[index] = "L"
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return 1
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return 0
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def count_neighbors(pos, grid):
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neighbors = 0
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x = pos % grid_width
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y = pos // grid_width
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for (dx, dy) in directions:
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xx = x + dx
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yy = y + dy
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if not in_bounds((xx, yy)):
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continue
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if grid[yy * grid_width + xx] == "#":
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neighbors += 1
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return neighbors
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def handle_empty_2(index, grid, next_grid):
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"""
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If a seat is empty and there are no occupied seat visible in neither direction,
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the seat becomes occupied
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"""
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neighbors = 0
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x = index % grid_width
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y = index // grid_width
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for direction in directions:
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# keep moving in the specified direction, while checking
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# that we are in bounds of the grid
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for xx, yy in takewhile(in_bounds, move(x, y, direction)):
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cell = grid[yy * grid_width + xx]
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if cell == "#":
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neighbors += 1
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elif cell == "L":
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break # No occupied seat in that direction, we can break
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if neighbors == 0:
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next_grid[index] = "#"
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return 1
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return 0
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def handle_occupied_2(index, grid, next_grid):
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"""
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An occupied seat becomes empty if there are five or more visible occupied
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seats in either direction.
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"""
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occupied = 0
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x = index % grid_width
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y = index // grid_width
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for direction in directions:
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for xx, yy in takewhile(in_bounds, move(x, y, direction)):
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print(xx, yy)
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cell = grid[yy * grid_width + xx]
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if cell == "#":
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occupied += 1
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if occupied >= 5:
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next_grid[index] = "L"
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return 1
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return 0
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def in_bounds(pos):
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x, y = pos
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return 0 <= x < grid_width and 0 <= y < grid_height
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def move(x, y, direction):
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pos = x, y
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while True:
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yield pos
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pos = x + direction[0], y + direction[1]
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part1_rules = {"L": handle_empty, "#": handle_occupied}
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part2_rules = {"L": handle_empty_2, "#": handle_occupied_2}
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