結果
| 問題 |
No.2238 Rock and Hole
|
| コンテスト | |
| ユーザー |
 shino16
|
| 提出日時 | 2023-02-06 09:38:08 |
| 言語 | Python3 (3.13.1 + numpy 2.2.1 + scipy 1.14.1) |
| 結果 |
AC
|
| 実行時間 | 921 ms / 3,000 ms |
| コード長 | 5,880 bytes |
| コンパイル時間 | 89 ms |
| コンパイル使用メモリ | 13,312 KB |
| 実行使用メモリ | 74,776 KB |
| 最終ジャッジ日時 | 2024-07-04 15:25:25 |
| 合計ジャッジ時間 | 6,749 ms |
|
ジャッジサーバーID （参考情報） |
judge2 / judge3 |
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| ファイルパターン | 結果 |
|---|---|
| other | AC * 24 |
ソースコード
from typing import NamedTuple, Optional, List, cast
# https://github.com/not522/ac-library-python/blob/master/atcoder/maxflow.py
class MFGraph:
class Edge(NamedTuple):
src: int
dst: int
cap: int
flow: int
class _Edge:
def __init__(self, dst: int, cap: int) -> None:
self.dst = dst
self.cap = cap
self.rev: Optional[MFGraph._Edge] = None
def __init__(self, n: int) -> None:
self._n = n
self._g: List[List[MFGraph._Edge]] = [[] for _ in range(n)]
self._edges: List[MFGraph._Edge] = []
def add_edge(self, src: int, dst: int, cap: int) -> int:
assert 0 <= src < self._n
assert 0 <= dst < self._n
assert 0 <= cap
m = len(self._edges)
e = MFGraph._Edge(dst, cap)
re = MFGraph._Edge(src, 0)
e.rev = re
re.rev = e
self._g[src].append(e)
self._g[dst].append(re)
self._edges.append(e)
return m
def get_edge(self, i: int) -> Edge:
assert 0 <= i < len(self._edges)
e = self._edges[i]
re = cast(MFGraph._Edge, e.rev)
return MFGraph.Edge(
re.dst,
e.dst,
e.cap + re.cap,
re.cap
)
def edges(self) -> List[Edge]:
return [self.get_edge(i) for i in range(len(self._edges))]
def change_edge(self, i: int, new_cap: int, new_flow: int) -> None:
assert 0 <= i < len(self._edges)
assert 0 <= new_flow <= new_cap
e = self._edges[i]
e.cap = new_cap - new_flow
assert e.rev is not None
e.rev.cap = new_flow
def flow(self, s: int, t: int, flow_limit: Optional[int] = None) -> int:
assert 0 <= s < self._n
assert 0 <= t < self._n
assert s != t
if flow_limit is None:
flow_limit = cast(int, sum(e.cap for e in self._g[s]))
current_edge = [0] * self._n
level = [0] * self._n
def fill(arr: List[int], value: int) -> None:
for i in range(len(arr)):
arr[i] = value
def bfs() -> bool:
fill(level, self._n)
queue = []
q_front = 0
queue.append(s)
level[s] = 0
while q_front < len(queue):
v = queue[q_front]
q_front += 1
next_level = level[v] + 1
for e in self._g[v]:
if e.cap == 0 or level[e.dst] <= next_level:
continue
level[e.dst] = next_level
if e.dst == t:
return True
queue.append(e.dst)
return False
def dfs(lim: int) -> int:
stack = []
edge_stack: List[MFGraph._Edge] = []
stack.append(t)
while stack:
v = stack[-1]
if v == s:
flow = min(lim, min(e.cap for e in edge_stack))
for e in edge_stack:
e.cap -= flow
assert e.rev is not None
e.rev.cap += flow
return flow
next_level = level[v] - 1
while current_edge[v] < len(self._g[v]):
e = self._g[v][current_edge[v]]
re = cast(MFGraph._Edge, e.rev)
if level[e.dst] != next_level or re.cap == 0:
current_edge[v] += 1
continue
stack.append(e.dst)
edge_stack.append(re)
break
else:
stack.pop()
if edge_stack:
edge_stack.pop()
level[v] = self._n
return 0
flow = 0
while flow < flow_limit:
if not bfs():
break
fill(current_edge, 0)
while flow < flow_limit:
f = dfs(flow_limit - flow)
flow += f
if f == 0:
break
return flow
def min_cut(self, s: int) -> List[bool]:
visited = [False] * self._n
stack = [s]
visited[s] = True
while stack:
v = stack.pop()
for e in self._g[v]:
if e.cap > 0 and not visited[e.dst]:
visited[e.dst] = True
stack.append(e.dst)
return visited
def main():
h, w = map(int, input().split())
S = [input() for _ in range(h)]
rocks = []
holes = []
for r, row in enumerate(S):
for c, x in enumerate(row):
if x == 'r':
rocks.append((r, c))
if x == 'h':
holes.append((r, c))
from bisect import bisect_left
def rix(r, c):
return bisect_left(rocks, (r, c))
def hix(r, c):
return bisect_left(holes, (r, c)) + n
n = len(rocks)
m = len(holes)
s = n + m
t = s + 1
G = MFGraph(t + 1)
for v in range(n):
G.add_edge(s, v, 1)
for v in range(m):
G.add_edge(n + v, t, 1)
for r, row in enumerate(S):
for it in [range(w), reversed(range(w))]:
prv = -1
for c in it:
if row[c] == 'r' and prv != -1:
G.add_edge(rix(r, c), hix(r, prv), 1)
if row[c] == 'h':
prv = c
for c, col in enumerate(zip(*S)):
for it in [range(h), reversed(range(h))]:
prv = -1
for r in it:
if col[r] == 'r' and prv != -1:
G.add_edge(rix(r, c), hix(prv, c), 1)
if col[r] == 'h':
prv = r
f = G.flow(s, t)
print('Yes' if f == n else 'No')
main()