結果

問題 No.1553 Lovely City
ユーザー aaaaaaaaaa2230
提出日時 2021-06-19 15:53:27
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 834 ms / 2,000 ms
コード長 1,709 bytes
コンパイル時間 383 ms
コンパイル使用メモリ 82,424 KB
実行使用メモリ 137,428 KB
最終ジャッジ日時 2024-06-22 22:07:07
合計ジャッジ時間 19,721 ms
ジャッジサーバーID
(参考情報)
judge1 / 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 deque
class Unionfind:
def __init__(self,n):
self.uf = [-1]*n
def find(self,x):
if self.uf[x] < 0:
return x
else:
self.uf[x] = self.find(self.uf[x])
return self.uf[x]
def same(self,x,y):
return self.find(x) == self.find(y)
def union(self,x,y):
x = self.find(x)
y = self.find(y)
if x == y:
return False
if self.uf[x] > self.uf[y]:
x,y = y,x
self.uf[x] += self.uf[y]
self.uf[y] = x
return True
def size(self,x):
x = self.find(x)
return -self.uf[x]
n,m = map(int,input().split())
uf = Unionfind(n+1)
e = [[] for i in range(n+1)]
deg = [0]*(n+1)
use = [0]*(n+1)
for _ in range(m):
u,v = map(int,input().split())
e[u].append(v)
uf.union(u,v)
use[u] = 1
use[v] = 1
deg[v] += 1
group = [[] for i in range(n+1)]
for i in range(n+1):
if use[i]:
group[uf.find(i)].append(i)
ans = []
for i in range(n+1):
if group[i] == []:
continue
q = deque([])
loop = 0
for ind in group[i]:
if deg[ind]:
continue
q.append(ind)
order = []
while q:
now = q.pop()
order.append(now)
for nex in e[now]:
deg[nex] -= 1
if deg[nex] == 0:
q.append(nex)
if len(order) == len(group[i]):
for x,y in zip(order,order[1:]):
ans.append((x,y))
else:
for j in range(len(group[i])):
x = group[i][j]
y = group[i][(j+1)%len(group[i])]
ans.append((x,y))
print(len(ans))
for x,y in ans:
print(x,y)
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