結果

問題 No.1553 Lovely City
ユーザー ygd.
提出日時 2021-06-19 18:31:09
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 1,055 ms / 2,000 ms
コード長 3,396 bytes
コンパイル時間 445 ms
コンパイル使用メモリ 82,404 KB
実行使用メモリ 175,448 KB
最終ジャッジ日時 2024-06-22 22:15:05
合計ジャッジ時間 23,250 ms
ジャッジサーバーID
(参考情報)
judge3 / judge2
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 * 2
other AC * 26
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

from collections import defaultdict
from collections import deque
class UnionFind(object):
def __init__(self, n=1):
self.par = [i for i in range(n)]
self.rank = [0 for _ in range(n)]
self.size = [1 for _ in range(n)]
def find(self, x):
"""
x
"""
if self.par[x] == x:
return x
else:
self.par[x] = self.find(self.par[x])
return self.par[x]
def union(self, x, y):
"""
x y
"""
x = self.find(x)
y = self.find(y)
if x != y:
if self.rank[x] < self.rank[y]:
x, y = y, x
if self.rank[x] == self.rank[y]:
self.rank[x] += 1
self.par[y] = x
self.size[x] += self.size[y]
def is_same(self, x, y):
"""
x y
"""
return self.find(x) == self.find(y)
def get_size(self, x):
"""
x
"""
x = self.find(x)
return self.size[x]
def topological(graph, deg):
start = []
for i in range(len(deg)):
if deg[i] == 0:
start.append(i)
topo = []
while start:
v = start.pop()
topo.append(v)
for u in graph[v]:
deg[u] -= 1
if deg[u] == 0:
start.append(u)
return topo
def main():
N,M = map(int,input().split())
Q = []
S = set([])
for i in range(M):
U,V = map(int,input().split())
Q.append((U,V))
S.add(U)
S.add(V)
L = list(S)
n = len(S) #
L.sort()
dic = {} #
revdic = {} #
for i in range(n):
dic[L[i]] = i
revdic[i] = L[i]
G = [[] for _ in range(n)]
deg = [0]*n
uf = UnionFind(n)
for u,v in Q:
uz = dic[u]
vz = dic[v]
G[uz].append(vz)
deg[vz] += 1
uf.union(uz,vz)
#print(G)
unidic = defaultdict(list)
for i in range(n):
par = uf.find(i)
unidic[par].append(i)
#
ans = []
for unit in unidic.values():
start = deque([])
for x in unit:
if deg[x] == 0:
start.append(x)
topo = []
while start:
v = start.pop()
topo.append(v)
for u in G[v]:
deg[u] -= 1
if deg[u] == 0:
start.append(u)
#print("U",unit)
#print("Topo",topo)
if len(topo) == len(unit): #
for i in range(len(topo)-1):
s = topo[i]; t = topo[i+1]
sori = revdic[s]; tori = revdic[t]
ans.append([sori,tori])
else:
if len(unit) == 1:
continue
else:
for i in range(len(unit)):
s = unit[i-1]; t = unit[i] #i==0
sori = revdic[s]; tori = revdic[t]
ans.append([sori,tori])
print(len(ans))
for ret in ans:
print(*ret)
if __name__ == '__main__':
main()
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