結果
| 問題 | No.421 しろくろチョコレート |
| コンテスト | |
| ユーザー |
 yura1685
|
| 提出日時 | 2026-08-13 02:46:52 |
| 言語 | PyPy3 (7.3.17) |
| 結果 |
AC
|
| 実行時間 | 204 ms / 2,000 ms |
| + 246µs | |
| コード長 | 5,267 bytes |
| 記録 | |
| コンパイル時間 | 226 ms |
| コンパイル使用メモリ | 96,100 KB |
| 実行使用メモリ | 94,592 KB |
| 最終ジャッジ日時 | 2026-08-13 02:47:11 |
| 合計ジャッジ時間 | 14,360 ms |
|
ジャッジサーバーID （参考情報） |
judge2_0 / judge3_0 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| other | AC * 65 |
ソースコード
from typing import NamedTuple, Optional, List, cast
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
H, W = map(int, input().split())
C = [input() for _ in range(H)]
g = MFGraph(H * W + 2)
S, T = H * W, H * W + 1
def f(h, w): return h * W + w
for h in range(H):
for w in range(W):
if C[h][w] == '.':
continue
if C[h][w] == 'b':
g.add_edge(f(h, w), T, 1)
continue
g.add_edge(S, f(h, w), 1)
for dh, dw in [(-1, 0), (0, -1), (0, 1), (1, 0)]:
nh, nw = h + dh, w + dw
if 0 <= nh < H and 0 <= nw < W and C[nh][nw] == 'b':
g.add_edge(f(h, w), f(nh, nw), 1)
white = sum(c.count('w') for c in C)
black = sum(c.count('b') for c in C)
flow = g.flow(S, T)
ans = 100 * flow
white, black = white - flow, black - flow
ans += 10 * min(white, black) + white + black - 2 * min(white, black)
print(ans)