mirror of
https://github.com/Threnklyn/advent-of-code-go.git
synced 2026-05-18 19:13:27 +02:00
alexchao26
109 lines
3.0 KiB
Python
109 lines
3.0 KiB
Python
import re
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def part1(input: str, wide: int, tall: int, seconds: int) -> int:
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# don't need to model this exactly right? just equate a line, mod by grid size...
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# i guess for 100 steps it would've been better to just model it...
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quad_counts: list[int] = [0] * 4
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for line in input.splitlines():
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nums = re.findall(r"-?\d+", line)
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assert len(nums) == 4
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x = int(nums[0]) + int(nums[2]) * seconds
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y = int(nums[1]) + int(nums[3]) * seconds
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x %= tall
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y %= wide
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if x < tall // 2 and y < wide // 2:
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# print("top left")
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quad_counts[0] += 1
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elif x < tall // 2 and y > wide // 2:
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# print("top right")
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quad_counts[1] += 1
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elif x > tall // 2 and y < wide // 2:
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# print("bottom left")
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quad_counts[2] += 1
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elif x > tall // 2 and y > wide // 2:
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# print("bottom right")
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quad_counts[3] += 1
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# else:
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# print("on mid line")
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# multiply robot count in each quadrant
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# does not include robots on mid-lines
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return quad_counts[0] * quad_counts[1] * quad_counts[2] * quad_counts[3]
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def part2(input: str, wide: int, tall: int) -> int:
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# i guess for 100 steps it would've been better to just model it...
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# then i could have reused it for part 2...
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robots: list[list[int]] = []
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for line in input.splitlines():
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nums = re.findall(r"-?\d+", line)
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assert len(nums) == 4
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robots.append([int(x) for x in nums])
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for s in range(10_000):
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neighbors: set[tuple[int, int]] = set()
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matched: set[tuple[int, int]] = set()
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for robot in robots:
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robot[0] += robot[2]
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robot[1] += robot[3]
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robot[0] %= tall
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robot[1] %= wide
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# track how many neighboring robots have been placed so far
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# when the number is high enough we probably have some image of a tree
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coord = (robot[0], robot[1])
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if coord in neighbors:
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matched.add(coord)
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for dx in [-1, 0, 1]:
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for dy in [-1, 0, 1]:
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neighbors.add((coord[0] + dx, coord[1] + dy))
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if len(matched) >= 250:
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print_grid(robots, wide, tall)
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# print(len(matched))
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return s + 1
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raise Exception("should return from loop")
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def print_grid(robots: list[list[int]], wide: int, tall: int):
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grid: list[list[str]] = []
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for _ in range(0, tall):
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grid.append([" "] * wide)
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for robot in robots:
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grid[robot[0]][robot[1]] = "X"
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for line in grid:
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print("".join(line))
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example = """p=0,4 v=3,-3
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p=6,3 v=-1,-3
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p=10,3 v=-1,2
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p=2,0 v=2,-1
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p=0,0 v=1,3
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p=3,0 v=-2,-2
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p=7,6 v=-1,-3
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p=3,0 v=-1,-2
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p=9,3 v=2,3
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p=7,3 v=-1,2
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p=2,4 v=2,-3
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p=9,5 v=-3,-3"""
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input = open("input.txt").read().strip()
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print(f"part1 example: {part1(example, 7, 11, 100)} want 12")
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print(f"part1 example: {part1(input, 103, 101, 100)} want 218965032")
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print(f"part2: {part2(input, 103, 101)} want 7037")
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