161 lines
4.4 KiB
Python
161 lines
4.4 KiB
Python
from lib import get_data, add2
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from collections import defaultdict
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data = "^WNE$"
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data = "^ENWWW(NEEE|SSE(EE|N))$"
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data = "^ESSWWN(E|NNENN(EESS(WNSE|)SSS|WWWSSSSE(SW|NNNE)))$"
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data = "^WSSEESWWWNW(S|NENNEEEENN(ESSSSW(NWSW|SSEN)|WSWWN(E|WWS(E|SS))))$"
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DIRS = {
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"N": (-1, 0),
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"E": (0, 1),
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"S": (1, 0),
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"W": (0, -1),
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}
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def part_1(data):
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g = defaultdict(set)
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stack: list[tuple[tuple, int, list]] = [((0, 0), 0, [])]
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while len(stack) > 0:
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pos, i, i_outs = stack.pop()
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assert i is not None
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while i < len(data):
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c = data[i]
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if c in DIRS.keys():
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npos = add2(pos, DIRS[c])
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g[pos].add(npos)
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g[npos].add(pos)
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pos = npos
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i += 1
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elif c == "(":
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to_continue = [i + 1]
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open_count = 0
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j_out = None
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for j in range(i + 1, len(data)):
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c = data[j]
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if c == "|" and open_count == 0:
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to_continue.append(j + 1)
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elif c == "(":
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open_count += 1
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elif c == ")" and open_count != 0:
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open_count -= 1
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elif c == ")" and open_count == 0:
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j_out = j
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break
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assert j_out is not None
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for new_i in to_continue:
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new_i_outs = list(i_outs)
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new_i_outs.append(j_out)
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stack.append((pos, new_i, new_i_outs))
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break
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elif c == "$":
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break
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elif c == ")" and len(i_outs) == 0:
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assert False, "Encountered | without i_out"
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elif c == ")":
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i_new = i_outs.pop()
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assert i == i_new
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i += 1
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elif c == "^":
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i += 1
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elif c == "|" and len(i_outs) == 0:
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assert False, "Encountered | without i_out"
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elif c == "|":
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i = i_outs.pop()
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i += 1
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else:
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assert False
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# def parse(i):
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# max_len = 0
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# cur_len = 0
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# while i < len(data):
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# c = data[i]
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# if c in DIRS.keys():
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# i += 1
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# cur_len += 1
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# elif c == "(":
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# sub_len, i = parse(i + 1)
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# cur_len += sub_len
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# elif c == "|":
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# max_len = max(max_len, cur_len)
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# cur_len = 0
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# i += 1
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# elif c == ")":
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# all_max = max(max_len, cur_len)
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# return all_max, i + 1
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# elif c == "$":
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# max_len = max(max_len, cur_len)
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# i += 1
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# else:
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# print(c)
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# assert False
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# return max_len, i
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#
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# print(parse(0)[0])
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# g = defaultdict(set)
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# def parse(xs, i):
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# xs_orig = xs.copy()
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# xs_done = []
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#
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# while i < len(data):
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# c = data[i]
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# if c in DIRS.keys():
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# for xi in range(len(xs)):
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# pos = xs[xi]
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# npos = add2(pos, DIRS[c])
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# g[pos].add(npos)
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# g[npos].add(pos)
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# xs[xi] = npos
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# i += 1
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# elif c == "(":
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# xs, i = parse(xs, i + 1)
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# elif c == "|":
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# xs_done += xs
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# xs = xs_orig
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# i += 1
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# elif c == ")":
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# xs_done += xs
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# return xs_done, i + 1
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# elif c == "$":
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# xs_done += xs
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# i += 1
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# else:
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# assert False
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# return xs_done, i
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#
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# parse([(0, 0)], 0)
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seen = set()
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dists = {}
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xs = [(0, 0)]
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steps = 0
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while len(xs) > 0:
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nxs = []
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for x in xs:
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if x in seen:
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continue
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seen.add(x)
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dists[x] = steps
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for nb in g[x]:
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if not nb in seen:
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nxs.append(nb)
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xs = nxs
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steps += 1
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print(max(dists.values()))
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def main():
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# data = get_data(__file__).strip()
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part_1(data)
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if __name__ == "__main__":
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main()
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