結果
問題 | No.1553 Lovely City |
ユーザー |
|
提出日時 | 2022-11-26 15:42:44 |
言語 | PyPy3 (7.3.15) |
結果 |
AC
|
実行時間 | 1,105 ms / 2,000 ms |
コード長 | 2,662 bytes |
コンパイル時間 | 205 ms |
コンパイル使用メモリ | 82,304 KB |
実行使用メモリ | 190,384 KB |
最終ジャッジ日時 | 2024-10-02 22:18:01 |
合計ジャッジ時間 | 25,409 ms |
ジャッジサーバーID (参考情報) |
judge1 / judge5 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 2 |
other | AC * 26 |
ソースコード
from collections import defaultdict, dequeclass UnionFind:__slots__ = ["n", "parent", "height", "size"]def __init__(self, n):self.n = nself.parent = [i for i in range(n)]self.height = [1] * nself.size = [1] * ndef find(self, x):if self.parent[x] == x:return xelse:self.parent[x] = self.find(self.parent[x])return self.parent[x]def unite(self, x, y):x = self.find(x)y = self.find(y)if x != y:if self.height[x] < self.height[y]:self.parent[x] = yself.size[y] += self.size[x]else:self.parent[y] = xself.size[x] += self.size[y]if self.height[x] == self.height[y]:self.height[x] += 1def issame(self, x, y):return self.find(x) == self.find(y)def group_size(self, x):return self.size[self.find(x)]def group_members(self, x):root = self.find(x)return [i for i in range(self.n) if self.find(i) == root]def roots(self):return [i for i, x in enumerate(self.parent) if i == x]def group_count(self):return len(self.roots())def topological_sort(nodes, edges):G = {n: [] for n in nodes}deg = {n: 0 for n in nodes}tps = []for a, b in edges:deg[b] += 1G[a].append(b)d = deque([i for i, x in deg.items() if not x])while d:v = d.popleft()tps.append(v)for x in G[v]:deg[x] -= 1if not deg[x]:d.append(x)if any(deg.values()):return None # not DAGreturn tpsN, M = map(int, input().split())uf = UnionFind(N)edges = tuple(tuple(int(x) - 1 for x in input().split()) for _ in range(M))for u, v in edges:uf.unite(u, v)cc_edges = defaultdict(list)cc_nodes = defaultdict(list)for i in range(N):cc_nodes[uf.find(i)].append(i)for u, v in edges:# assert uf.find(u) == uf.find(v)cc_edges[uf.find(u)].append((u, v))ans = []for root in uf.roots():nodes = cc_nodes[root]if len(nodes) == 1:continueedges = cc_edges[root]tps = topological_sort(nodes, edges)if tps is None:# 適当なサイクルfor i in range(len(nodes)):j = i + 1if j == len(nodes):j = 0ans.append((nodes[i], nodes[j]))else:# DAGfor i in range(len(tps) - 1):ans.append((tps[i], tps[i + 1]))print(len(ans))for u, v in ans:print(u + 1, v + 1)