Anders Englöf Ytterström
1e807b5daf
Initial version of the code tried to solve pt 1 using BFS, which took way too long even for the test data. After some fiddling with algebra with pen and paper, I realized this 2 formulaes (using first example): 94 * b1 + 22 * b2 == 840 34 * b1 + 67 * b2 == 540 *b1 = button A presses *b2 = button B presses ... could be rewritten to this single expression: (94 + 34) * b1 + (22 + 67) * b2 = 840 * 540 I failed to remember the algebra for solving x than y though, that I had to learn from the subreddit. In the code, this is the ratio part. Also, this solution using fractions is SICK. https://www.reddit.com/r/adventofcode/comments/1hd4wda/comment/m1tz3nf/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button
88 lines
2.4 KiB
Python
88 lines
2.4 KiB
Python
import re
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from collections import Counter, defaultdict, deque
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from heapq import heappop, heappush
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from itertools import chain, combinations, compress, permutations
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from output import ADJ, DD, D, ccw, cw, ints, matrix, mdbg, mhd, vdbg
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def solve(data):
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grid, H, W = matrix(data)
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p1 = 0
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seen = set()
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for r, row in enumerate(grid):
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for c, col in enumerate(row):
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if (r, c) in seen:
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continue
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areas = 0
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perimeters = 0
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q = deque([(r, c)])
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while q:
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rc = q.popleft()
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if rc in seen:
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continue
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seen.add(rc)
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areas += 1
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y, x = rc
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for dy, dx in D:
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if (0 <= y + dy < H and 0 <= x + dx < W) and grid[y + dy][
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x + dx
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] == col:
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q.append((y + dy, x + dx))
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else:
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perimeters += 1
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p1 += areas * perimeters
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p2 = None
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return p1, p2
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if __name__ == "__main__":
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import os
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# use dummy data
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inp = """
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RRRRIICCFF
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RRRRIICCCF
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VVRRRCCFFF
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VVRCCCJFFF
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VVVVCJJCFE
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VVIVCCJJEE
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VVIIICJJEE
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MIIIIIJJEE
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MIIISIJEEE
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MMMISSJEEE
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""".strip()
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"""
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A region of R plants with price 12 * 18 = 216.
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A region of I plants with price 4 * 8 = 32.
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A region of C plants with price 14 * 28 = 392.
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A region of F plants with price 10 * 18 = 180.
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A region of V plants with price 13 * 20 = 260.
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A region of J plants with price 11 * 20 = 220.
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A region of C plants with price 1 * 4 = 4.
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A region of E plants with price 13 * 18 = 234.
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A region of I plants with price 14 * 22 = 308.
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A region of M plants with price 5 * 12 = 60.
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A region of S plants with price 3 * 8 = 24.
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"""
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# uncomment to instead use stdin
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# import sys; inp = sys.stdin.read().strip()
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# uncomment to use AoC provided puzzle input
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with open("./input/12.txt", "r") as f:
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inp = f.read().strip()
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# uncomment to do initial data processing shared by part 1-2
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p1, p2 = solve(inp)
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print(p1)
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os.system(f"echo {p1} | wl-copy")
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# print(p2)
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# os.system(f"echo {p2} | wl-copy")
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# uncomment and replace 0 with actual output to refactor code
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# and ensure nonbreaking changes
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assert p1 == 1446042
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# assert p2 == 0
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