結果

問題 No.470 Inverse S+T Problem
ユーザー H20H20
提出日時 2021-02-09 14:03:35
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 136 ms / 2,000 ms
コード長 5,299 bytes
コンパイル時間 151 ms
コンパイル使用メモリ 82,036 KB
実行使用メモリ 86,372 KB
最終ジャッジ日時 2024-12-22 14:04:31
合計ジャッジ時間 3,882 ms
ジャッジサーバーID
(参考情報)
judge3 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 4
other AC * 27
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

import types
_atcoder_code = """
# Python port of AtCoder Library.
__version__ = '0.0.1'
"""
atcoder = types.ModuleType('atcoder')
exec(_atcoder_code, atcoder.__dict__)
_atcoder__scc_code = """
import copy
import sys
import typing
class CSR:
def __init__(
self, n: int, edges: typing.List[typing.Tuple[int, int]]) -> None:
self.start = [0] * (n + 1)
self.elist = [0] * len(edges)
for e in edges:
self.start[e[0] + 1] += 1
for i in range(1, n + 1):
self.start[i] += self.start[i - 1]
counter = copy.deepcopy(self.start)
for e in edges:
self.elist[counter[e[0]]] = e[1]
counter[e[0]] += 1
class SCCGraph:
'''
Reference:
R. Tarjan,
Depth-First Search and Linear Graph Algorithms
'''
def __init__(self, n: int) -> None:
self._n = n
self._edges = []
def num_vertices(self) -> int:
return self._n
def add_edge(self, from_vertex: int, to_vertex: int) -> None:
self._edges.append((from_vertex, to_vertex))
def scc_ids(self) -> typing.Tuple[int, typing.List[int]]:
g = CSR(self._n, self._edges)
now_ord = 0
group_num = 0
visited = []
low = [0] * self._n
order = [-1] * self._n
ids = [0] * self._n
sys.setrecursionlimit(max(self._n + 1000, sys.getrecursionlimit()))
def dfs(v: int) -> None:
nonlocal now_ord
nonlocal group_num
nonlocal visited
nonlocal low
nonlocal order
nonlocal ids
low[v] = now_ord
order[v] = now_ord
now_ord += 1
visited.append(v)
for i in range(g.start[v], g.start[v + 1]):
to = g.elist[i]
if order[to] == -1:
dfs(to)
low[v] = min(low[v], low[to])
else:
low[v] = min(low[v], order[to])
if low[v] == order[v]:
while True:
u = visited[-1]
visited.pop()
order[u] = self._n
ids[u] = group_num
if u == v:
break
group_num += 1
for i in range(self._n):
if order[i] == -1:
dfs(i)
for i in range(self._n):
ids[i] = group_num - 1 - ids[i]
return group_num, ids
def scc(self) -> typing.List[typing.List[int]]:
ids = self.scc_ids()
group_num = ids[0]
counts = [0] * group_num
for x in ids[1]:
counts[x] += 1
groups = [[] for _ in range(group_num)]
for i in range(self._n):
groups[ids[1][i]].append(i)
return groups
"""
atcoder._scc = types.ModuleType('atcoder._scc')
exec(_atcoder__scc_code, atcoder._scc.__dict__)
_atcoder_twosat_code = """
import typing
# import atcoder._scc
class TwoSAT:
'''
Reference:
B. Aspvall, M. Plass, and R. Tarjan,
A Linear-Time Algorithm for Testing the Truth of Certain Quantified Boolean
Formulas
'''
def __init__(self, n: int = 0) -> None:
self._n = n
self._answer = [False] * n
self._scc = atcoder._scc.SCCGraph(2 * n)
def add_clause(self, i: int, f: bool, j: int, g: bool) -> None:
assert 0 <= i < self._n
assert 0 <= j < self._n
self._scc.add_edge(2 * i + (0 if f else 1), 2 * j + (1 if g else 0))
self._scc.add_edge(2 * j + (0 if g else 1), 2 * i + (1 if f else 0))
def satisfiable(self) -> bool:
scc_id = self._scc.scc_ids()[1]
for i in range(self._n):
if scc_id[2 * i] == scc_id[2 * i + 1]:
return False
self._answer[i] = scc_id[2 * i] < scc_id[2 * i + 1]
return True
def answer(self) -> typing.List[bool]:
return self._answer
"""
atcoder.twosat = types.ModuleType('atcoder.twosat')
atcoder.twosat.__dict__['atcoder'] = atcoder
atcoder.twosat.__dict__['atcoder._scc'] = atcoder._scc
exec(_atcoder_twosat_code, atcoder.twosat.__dict__)
TwoSAT = atcoder.twosat.TwoSAT
# https://atcoder.jp/contests/practice2/tasks/practice2_h
import sys
# from atcoder.twosat import TwoSAT
def main() -> None:
N = int(input())
S = []
for i in range(N):
S.append(input())
if N>52:
print('Impossible')
return
two_sat = TwoSAT(N)
for i in range(N):
for j in range(i + 1, N):
if S[i][:2]==S[j][:2] or S[i][2]==S[j][2]:
two_sat.add_clause(i, 0, j, 0)
if S[i][:2]==S[j][1:] or S[i][2]==S[j][0]:
two_sat.add_clause(i, 0, j, 1)
if S[i][1:]==S[j][:2] or S[i][0]==S[j][2]:
two_sat.add_clause(i, 1, j, 0)
if S[i][1:]==S[j][1:] or S[i][0]==S[j][0]:
two_sat.add_clause(i, 1, j, 1)
if not two_sat.satisfiable():
print("Impossible")
else:
answer = two_sat.answer()
for i in range(N):
if answer[i]:
print(S[i][0]+S[i][1]+' '+S[i][2])
else:
print(S[i][0]+' '+S[i][1]+S[i][2])
if __name__ == '__main__':
main()
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