結果

問題 No.697 池の数はいくつか
ユーザー ntuda
提出日時 2025-01-21 22:09:39
言語 PyPy3
(7.3.15)
結果
MLE  
実行時間 -
コード長 2,237 bytes
コンパイル時間 2,862 ms
コンパイル使用メモリ 82,584 KB
実行使用メモリ 813,744 KB
最終ジャッジ日時 2025-01-21 22:10:29
合計ジャッジ時間 33,123 ms
ジャッジサーバーID
(参考情報)
judge5 / judge1
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 * 3
other AC * 26 MLE * 6
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 typing
class DSU:
'''
Implement (union by size) + (path halving)
Reference:
Zvi Galil and Giuseppe F. Italiano,
Data structures and algorithms for disjoint set union problems
'''
def __init__(self, n: int = 0) -> None:
self._n = n
self.parent_or_size = [-1] * n
def merge(self, a: int, b: int) -> int:
assert 0 <= a < self._n
assert 0 <= b < self._n
x = self.leader(a)
y = self.leader(b)
if x == y:
return x
if -self.parent_or_size[x] < -self.parent_or_size[y]:
x, y = y, x
self.parent_or_size[x] += self.parent_or_size[y]
self.parent_or_size[y] = x
return x
def same(self, a: int, b: int) -> bool:
assert 0 <= a < self._n
assert 0 <= b < self._n
return self.leader(a) == self.leader(b)
def leader(self, a: int) -> int:
assert 0 <= a < self._n
parent = self.parent_or_size[a]
while parent >= 0:
if self.parent_or_size[parent] < 0:
return parent
self.parent_or_size[a], a, parent = (
self.parent_or_size[parent],
self.parent_or_size[parent],
self.parent_or_size[self.parent_or_size[parent]]
)
return a
def size(self, a: int) -> int:
assert 0 <= a < self._n
return -self.parent_or_size[self.leader(a)]
def groups(self) -> typing.List[typing.List[int]]:
leader_buf = [self.leader(i) for i in range(self._n)]
result: typing.List[typing.List[int]] = [[] for _ in range(self._n)]
for i in range(self._n):
result[leader_buf[i]].append(i)
return list(filter(lambda r: r, result))
H, W = map(int, input().split())
HW = H * W
A = [list(map(int, input().split())) for _ in range(H)]
dsu = DSU(HW + 1)
for h in range(H):
for w in range(W):
if A[h][w] == 0:
dsu.merge(h * W + w, HW)
continue
if 0 < h and A[h][w] == A[h - 1][w]:
dsu.merge(h * W + w, (h - 1) * W + w)
if 0 < w and A[h][w] == A[h][w - 1]:
dsu.merge(h * W + w, h * W + w - 1)
print(len(dsu.groups()) - 1)
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