My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add solution for 2024/18
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+49
2024/day18.py
+49
2024/day18.py
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import fileinput
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from collections import deque
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from utils import Point, parse_nums
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def bfs(size, corruptions, time, start, end):
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horizon = deque([(start, 0)])
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seen = set()
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while horizon:
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pos, dist = horizon.popleft()
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if pos in seen:
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continue
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seen.add(pos)
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if pos == END:
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return dist
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for n in pos.neighbours():
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is_corrupted = corruptions.get(n, 1e6)
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if is_corrupted < time:
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continue
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if 0 <= n.x <= size and 0 <= n.y <= size:
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horizon.append((n, dist + 1))
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SIZE = 70
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# Read problem input.
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BYTES = []
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CORRUPTIONS = {}
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for i, line in enumerate(fileinput.input()):
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BYTES.append(line)
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x, y = parse_nums(line)
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CORRUPTIONS[Point(x, y)] = i
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START = Point(0, 0)
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END = Point(SIZE, SIZE)
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# Solve problem.
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for i in range(len(BYTES)):
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dist = bfs(SIZE, CORRUPTIONS, i, Point(0, 0), Point(SIZE, SIZE))
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if i == 1024:
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print("Part 1:", dist)
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if dist is None:
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print("Part 2:", BYTES[i-1])
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break