結果

問題 No.2238 Rock and Hole
ユーザー shino16shino16
提出日時 2023-02-06 09:39:20
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 642 ms / 3,000 ms
コード長 5,852 bytes
コンパイル時間 174 ms
コンパイル使用メモリ 82,156 KB
実行使用メモリ 141,620 KB
最終ジャッジ日時 2024-07-04 15:26:29
合計ジャッジ時間 5,660 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge2
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 64 ms
69,428 KB
testcase_01 AC 64 ms
68,652 KB
testcase_02 AC 63 ms
69,428 KB
testcase_03 AC 62 ms
68,768 KB
testcase_04 AC 63 ms
69,660 KB
testcase_05 AC 62 ms
68,972 KB
testcase_06 AC 63 ms
69,088 KB
testcase_07 AC 63 ms
68,896 KB
testcase_08 AC 63 ms
69,052 KB
testcase_09 AC 64 ms
69,356 KB
testcase_10 AC 127 ms
81,016 KB
testcase_11 AC 155 ms
105,028 KB
testcase_12 AC 155 ms
103,336 KB
testcase_13 AC 148 ms
104,212 KB
testcase_14 AC 123 ms
90,920 KB
testcase_15 AC 131 ms
82,836 KB
testcase_16 AC 403 ms
140,124 KB
testcase_17 AC 519 ms
141,620 KB
testcase_18 AC 253 ms
116,108 KB
testcase_19 AC 642 ms
111,624 KB
testcase_20 AC 404 ms
111,960 KB
testcase_21 AC 435 ms
110,880 KB
testcase_22 AC 329 ms
101,328 KB
testcase_23 AC 63 ms
69,608 KB
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 # 

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 in range(h):
        for c, x in enumerate(S[r]):
            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 in range(h):
        for it in [range(w), reversed(range(w))]:
            prv = -1
            for c in it:
                if S[r][c] == 'r' and prv != -1:
                    G.add_edge(rix(r, c), hix(r, prv), 1)
                if S[r][c] == 'h':
                    prv = c

    for c in range(w):
        for it in [range(h), reversed(range(h))]:
            prv = -1
            for r in it:
                if S[r][c] == 'r' and prv != -1:
                    G.add_edge(rix(r, c), hix(prv, c), 1)
                if S[r][c] == 'h':
                    prv = r

    f = G.flow(s, t)
    print('Yes' if f == n else 'No')

main()
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