Anders Englöf Ytterström
1b6502df7a
Hard one. Comparing to earlier years, the difficulty level seems higher than usual. I blame the LLM hipsters. This one I asumed, but missed when I tried to find it: > "If a block contains free space, skip it instead." Lucky me.
67 lines
1.8 KiB
Python
67 lines
1.8 KiB
Python
from collections import deque
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def solve(data):
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blocks_checksum = defrag(data)
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files_checksum = defrag(data, True)
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return blocks_checksum, files_checksum
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def defrag(data, move_files=False):
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expected_seq_len = sum(map(int, data[::2]))
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seq = dict()
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gaps = dict()
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q = deque([])
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i = 0
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for fileid, pair in enumerate(zip(data[::2], data[1::2] + "0")):
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size, free = map(int, pair)
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q.append((i, fileid, size))
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for _ in range(int(size)):
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seq[i] = fileid
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i += 1
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gaps[i] = free
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i += int(free)
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while q:
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i, fileid, size = q.pop()
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if move_files:
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updated = False
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for pos, space in gaps.items():
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if pos > i:
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continue
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if size <= space:
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rem = space - size
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updated = True
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break
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if updated:
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for k in range(size):
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seq[pos + k] = fileid
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for k in range(i, i + size):
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del seq[k]
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del gaps[pos]
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gaps[pos + size] = rem
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gaps = dict(sorted(gaps.items(), key=lambda x: x[0]))
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else:
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move = False
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for j in range(size):
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for k in range(expected_seq_len):
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if k not in seq:
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seq[k] = fileid
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del seq[i + j]
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move = True
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break
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if not move:
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break
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return sum(
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pos * id
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for pos, id in enumerate(seq.get(fileid, 0) for fileid in range(max(seq) + 1))
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)
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if __name__ == "__main__":
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with open("./input/09.txt", "r") as f:
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inp = f.read().strip()
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p1, p2 = solve(inp)
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print(p1)
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print(p2)
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