結果

問題 No.1865 Make Cycle
ユーザー tassei903
提出日時 2022-03-11 12:36:50
言語 PyPy3
(7.3.15)
結果
RE  
実行時間 -
コード長 1,957 bytes
コンパイル時間 524 ms
コンパイル使用メモリ 82,688 KB
実行使用メモリ 198,624 KB
最終ジャッジ日時 2024-09-15 12:41:07
合計ジャッジ時間 32,889 ms
ジャッジサーバーID
(参考情報)
judge2 / judge4
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 * 19 RE * 1
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

import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################
# (SCC): GSCC
# : <N>: , <G>: , <RG>:
# : (<>, <>)
def scc(N, G, RG, y):
order = []
used = [0]*N
group = [None]*N
def dfs(s):
used[s] = 1
for t,x in G[s]:
if x > y:
continue
if not used[t]:
dfs(t)
order.append(s)
def rdfs(s, col):
group[s] = col
used[s] = 1
for t, x in RG[s]:
if x > y:
continue
if not used[t]:
rdfs(t, col)
for i in range(N):
if not used[i]:
dfs(i)
used = [0]*N
label = 0
for s in reversed(order):
if not used[s]:
rdfs(s, label)
label += 1
return label, group
#
def construct(N, G, label, group):
G0 = [set() for i in range(label)]
GP = [[] for i in range(label)]
for v in range(N):
lbs = group[v]
for w in G[v]:
lbt = group[w]
if lbs == lbt:
continue
G0[lbs].add(lbt)
GP[lbs].append(v)
return G0, GP
n,q = na()
g = [[] for i in range(n)]
rg = [[] for i in range(n)]
for j in range(q):
a,b = na()
a-=1
b-=1
g[a].append((b,j))
rg[b].append((a, j))
ok = q
ng = -1
while (ok-ng)>1:
d = (ok+ng)//2
if scc(n,g,rg,d)[0]<n:
ok = d
else:
ng = d
if ok == q:
print(-1)
else:
print(ok+1)
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