結果

問題 No.2780 The Bottle Imp
コンテスト
ユーザー rin204
提出日時 2024-06-07 21:41:12
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 266 ms / 2,000 ms
コード長 2,875 bytes
コンパイル時間 374 ms
コンパイル使用メモリ 82,472 KB
実行使用メモリ 113,260 KB
最終ジャッジ日時 2024-12-27 13:36:47
合計ジャッジ時間 8,190 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge3
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 * 40
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 # 

class SCC:
    def __init__(self, n, edges=None):
        self.n = n
        if edges is None:
            self.edges = []
        else:
            self.edges = edges

    def add_edge(self, u, v):
        self.edges.append((u, v))

    def read_edges(self, m, indexed=1):
        for _ in range(m):
            u, v = map(int, input().split())
            u -= indexed
            v -= indexed
            self.add_edge(u, v)

    def build(self):
        start = [0] * (self.n + 1)
        elist = [0] * len(self.edges)
        for u, _ in self.edges:
            start[u + 1] += 1
        for i in range(1, self.n + 1):
            start[i] += start[i - 1]

        counter = start[:]
        for u, v in self.edges:
            elist[counter[u]] = v
            counter[u] += 1

        now_ord = 0
        group_num = 0
        visited = []
        low = [0] * self.n
        ord = [-1] * self.n
        ids = [0] * self.n
        bpos = [-1] * self.n

        def dfs(v):
            nonlocal now_ord, group_num

            visited.append(v)
            stack = [~v, v]
            while stack:
                pos = stack.pop()
                if pos >= 0:
                    if ord[pos] == -1:
                        low[pos] = ord[pos] = now_ord
                        now_ord += 1
                        visited.append(pos)
                        for i in range(start[pos], start[pos + 1]):
                            to = elist[i]
                            if ord[to] == -1:
                                stack.append(~to)
                                stack.append(to)
                                bpos[to] = pos
                            else:
                                low[pos] = min(low[pos], ord[to])
                else:
                    pos = ~pos
                    if low[pos] == ord[pos]:
                        while 1:
                            u = visited.pop()
                            ord[u] = self.n
                            ids[u] = group_num
                            if u == pos:
                                break
                        group_num += 1
                    if bpos[pos] != -1:
                        low[bpos[pos]] = min(low[bpos[pos]], low[pos])

        for i in range(self.n):
            if ord[i] == -1:
                dfs(i)

        for i in range(self.n):
            ids[i] = group_num - 1 - ids[i]

        return group_num, ids

n = int(input())
G = SCC(n)
edges = [[] for _ in range(n)]
for i in range(n):
    m, *A = map(int, input().split())
    for a in A:
        a -= 1
        G.add_edge(i, a)
        edges[i].append(a)

l, ids = G.build()
if ids[0] != 0:
    print("No")
    exit()
ok = [False] * (l - 1)
for i in range(n):
    for j in edges[i]:
        if ids[i] + 1 == ids[j]:
            ok[ids[i]] = True

if all(ok):
    print("Yes")
else:
    print("No")
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