input stringlengths 20 127k | target stringlengths 20 119k | problem_id stringlengths 6 6 |
|---|---|---|
import sys
N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
l = 1
p = a[0] - 1
if a[0] == 2:
print(l)
sys.exit()
while l < int(1e6):
l += 1
if a[p] == 2:
print(l)
break
else:
p = a[p] - 1
else:
print((-1)) | import sys
N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
l = 1
p = a[0] - 1
if a[0] == 2:
print(l)
sys.exit()
while l < int(2e5):
l += 1
if a[p] == 2:
print(l)
break
else:
p = a[p] - 1
else:
print((-1)) | p03680 |
n = int(eval(input()))
a = []
b = []
for i in range(n):
a.append(int(eval(input())))
b.append(0)
# 1: now, -1: visited, 0: none
b[0] = 1
now = 0
count = 0
while (b[1] != 1):
next = a[now] - 1
if (b[next] == -1):
print((-1))
exit()
b[now] = -1
b[next] = 1
now = next
count += 1
print(count)
| n = int(eval(input()))
a = []
b = []
for i in range(n):
a.append(int(eval(input())))
b.append(0)
# 1: now, -1: visited, 0: none
b[0] = 1
now = 0
count = 0
while (b[1] != 1 and count <= n):
next = a[now] - 1
if (b[next] == -1):
print((-1))
exit()
b[now] = -1
b[next] = 1
now = next
count += 1
if (b[1] == 1):
print(count)
else:
print((-1))
| p03680 |
N = int(eval(input()))
A=[]
l=[1]
ans=0
for i in range(N):
A.append(int(eval(input())))
for i in range(N):
l.append(A[l[i]-1])
if l[i+1]==2:
ans=i+1
break
if l[i+1]in l[:i]:
break
if ans!=0:
print(ans)
else:
print((-1)) | N = int(eval(input()))
A=[]
l=[1]
ans=0
for i in range(N):
A.append(int(eval(input())))
for i in range(N):
l.append(A[l[i]-1])
if l[i+1]==2:
ans=i+1
break
if ans!=0:
print(ans)
else:
print((-1)) | p03680 |
# Author: cr4zjh0bp
# Created: Sun Mar 22 23:25:40 UTC 2020
import sys
stdin = sys.stdin
inf = 1 << 60
mod = 1000000007
ni = lambda: int(ns())
nin = lambda y: [ni() for _ in range(y)]
na = lambda: list(map(int, stdin.readline().split()))
nan = lambda y: [na() for _ in range(y)]
nf = lambda: float(ns())
nfn = lambda y: [nf() for _ in range(y)]
nfa = lambda: list(map(float, stdin.readline().split()))
nfan = lambda y: [nfa() for _ in range(y)]
ns = lambda: stdin.readline().rstrip()
nsn = lambda y: [ns() for _ in range(y)]
ncl = lambda y: [list(ns()) for _ in range(y)]
nas = lambda: stdin.readline().split()
n = ni()
a = nin(n)
ans = 0
flag = True
i = 0
p = 0
while i != 1:
if p == a[i] - 1:
flag = False
break
p = i
i = a[i] - 1
ans += 1
print((ans if flag else -1)) | # Author: cr4zjh0bp
# Created: Sun Mar 22 23:25:40 UTC 2020
import sys
stdin = sys.stdin
inf = 1 << 60
mod = 1000000007
ni = lambda: int(ns())
nin = lambda y: [ni() for _ in range(y)]
na = lambda: list(map(int, stdin.readline().split()))
nan = lambda y: [na() for _ in range(y)]
nf = lambda: float(ns())
nfn = lambda y: [nf() for _ in range(y)]
nfa = lambda: list(map(float, stdin.readline().split()))
nfan = lambda y: [nfa() for _ in range(y)]
ns = lambda: stdin.readline().rstrip()
nsn = lambda y: [ns() for _ in range(y)]
ncl = lambda y: [list(ns()) for _ in range(y)]
nas = lambda: stdin.readline().split()
n = ni()
a = nin(n)
i = 0
ans = 0
flag = True
while i != 1:
if ans > n:
flag = False
break
i = a[i] - 1
ans += 1
print((ans if flag else -1)) | p03680 |
from collections import deque
n=int(eval(input()))
blist=deque([int(eval(input())) for a in range(n)])
vlist=deque([1])
while True:
if 2 == vlist[-1]:
print((len(vlist)-1))
break
a=blist[vlist[-1]-1]
if a in deque([a for a in vlist]):
print((-1))
break
else:
vlist.append(a) | from collections import deque
n=int(eval(input()))
blist=deque([int(eval(input())) for a in range(n)])
vlist=1
count=0
while True:
if count>n:
print((-1))
break
if 2 == vlist:
print(count)
break
vlist=blist[vlist-1]
count+=1 | p03680 |
N=int(eval(input()))
x=[int(eval(input())) for _ in range(N)]
#x=dict(zip(range(1,N+1),a))
#print(x)
route=[1,]
#for _ in range(N):
while 2 not in route:
#print(x[route[-1]])
if route[-1]==2:
break
elif x[route[-1]-1] not in route:
route.append(x[route[-1]-1])
else:
print((-1))
exit()
print((len(route)-1)) | N=int(eval(input()))
x=[int(eval(input())) for _ in range(N)]
on=1
ans=0
for _ in range(N):
on=x[on-1]
ans=ans+1
if on==2:
print(ans)
exit()
print((-1)) | p03680 |
a = int(eval(input()))
b = [[int(eval(input())), False]for i in range(a)]
c = 1
d = 0
while True:
d += 1
if b[c-1][0] == 2:
print(d)
exit()
else:
b[c-1][1] = not b[c-1][1]
if b[c-1][1]:
c = b[c-1][0]
else:
print((-1))
exit()
| a = int(eval(input()))
b = [int(eval(input())) for _ in range(a)]
c = 1
d = 0
e = {}
while True:
d += 1
if b[c-1] == 2:
print(d)
exit()
else:
if (c-1) not in e:
e.setdefault((c-1), "")
else:
print((-1))
exit()
c = b[c - 1]
| p03680 |
N = int(eval(input()))
array = []
for i in range(N):
a = int(eval(input()))-1
array.append(a)
c = 0
now = 0
for i in range(N):
now = array[now]
c += 1
if now == 1:
break
if c == N and now != 1:
print((-1))
else:
print(c) | N = int(eval(input()))
a = [int(eval(input())) for i in range(N)]
nexta = a[0]
ans = -1
for i in range(1,N):
if nexta == 2:
ans = i
break
nexta = a[nexta-1]
print(ans) | p03680 |
def training():
N = int(eval(input()))
A = [0]
for i in range(N):
A.append(int(eval(input())))
counter = 1
index = 1
judge = [1]
if A[index] == 2:
print(counter)
return
counter += 1
index = A[index]
for i in range(N):
if A[index] in judge:
print("-1")
return
if A[index] == 2:
print(counter)
return
counter += 1
judge.append(A[index])
index = A[index]
training()
| def training():
N = int(eval(input()))
A = [0]
for i in range(N):
A.append(int(eval(input())))
counter = 1
index = 1
#judge = [1]
if A[index] == 2:
print(counter)
return
counter += 1
index = A[index]
for i in range(N):
#if A[index] in judge:
#print("-1")
#return
if A[index] == 2:
print(counter)
return
counter += 1
#judge.append(A[index])
index = A[index]
print("-1")
training()
| p03680 |
n = int(eval(input()))
a = list(map(int, list(eval(input()) for _ in range(n))))
visited = list(False for _ in range(n))
if (2 in a) == False:
print((-1))
exit()
idx = 1
cnt = 0
while True:
cnt += 1
if a[idx - 1] == 2:
print(cnt)
exit()
else:
if visited[idx - 1] == True:
print((-1))
exit()
else:
visited[idx - 1] = True
idx = a[idx - 1] ##次のボタン | def main():
import sys
input = sys.stdin.readline
N = int(eval(input()))
a = [int(eval(input())) - 1 for _ in range(N)]
cur = 0
cnt = [-1] * N
cnt[0] = 0
while cur != 1:
c = cnt[cur]
cur = a[cur]
if ~cnt[cur]: break
cnt[cur] = c + 1
print((cnt[1] if ~cnt[1] else -1))
if __name__ == '__main__':
main()
| p03680 |
# -*- coding: utf-8 -*-
n = int(eval(input()))
a = [0] * n
for i in range(n):
a[i] = int(eval(input()))
cnt = 0
lit = 0
while lit != 1 and (lit != 0 or cnt == 0):
lit = a[lit] - 1
cnt += 1
if lit == 1:
print(cnt)
else:
print((-1))
| N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
i = 0
done = {a - 1: False for a in A}
num = 0
while True:
i = A[i] - 1
num += 1
if i == 1:
print(num)
exit()
if done[i]:
print((-1))
exit()
done[i] = True | p03680 |
n = int(eval(input()))
a = [int(eval(input())) for _ in range(n)]
c,s = 1,a[0]
while s != 2 and c < n:c,s = c+1,a[s-1]
print((c if c < n else "-1")) | n = int(eval(input()))
a = [int(eval(input())) for _ in range(n)]
c,s = 1,a[0]
while c <= n and s != 2:c,s = c+1,a[s-1]
print((c if c <= n else "-1")) | p03680 |
n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
l = [1]
bot = 1
for i in range(n):
bot = a[bot - 1]
if bot == 2:
print((i + 1))
break
if bot in l:
print((-1))
break
else:
l.append(bot) | n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
l = [1]
bot = 1
flag = True
for i in range(n):
bot = a[bot - 1]
if bot == 2:
print((i + 1))
flag = False
break
if flag:
print((-1)) | p03680 |
n = int(eval(input()))
a = []
for i in range(n):
a_ = int(eval(input()))
a.append(a_)
res = []
i = 1
for _ in range(n):
res.append(a[i-1])
i = a[i-1]
if i == 2:
break
if 2 in res:
print((len(res)))
else:
print((-1)) | n = int(eval(input()))
a = []
for _ in range(n):
a_ = int(eval(input()))
a.append(a_)
ans = 0
c = 1
for i in range(n):
c = a[c-1]
ans += 1
if c == 2:
print(ans)
exit()
print((-1)) | p03680 |
n = int(eval(input()))
a = []
for _ in range(n):
a_ = int(eval(input()))
a.append(a_)
ans = 0
c = 1
for i in range(n):
c = a[c-1]
ans += 1
if c == 2:
print(ans)
exit()
print((-1)) | n=int(eval(input()))
a=[int(eval(input())) for i in range(n)]
ans=1
res=1
for i in range(n):
if a[res-1]==2:
print(ans)
exit()
else:
ans+=1
res=a[res-1]
print((-1)) | p03680 |
n = int(eval(input()))
a = [0] + [int(eval(input())) for _ in range(n)]
pos = 1
cnt = 0
while True:
cnt += 1
if a[pos] == 1:
print((-1))
break
elif a[pos] == 2:
print(cnt)
break
pos = a[pos]
| n = int(eval(input()))
a = [0] + [int(eval(input())) for _ in range(n)]
pos = 1
for i in range(n):
pos = a[pos]
if pos == 2:
print((i+1))
break
else:
print((-1))
| p03680 |
def main():
n = int(eval(input()))
a = [0]*n
for i in range(n):
a[i] += int(eval(input()))
s = 1
for i in range(n):
if a[s-1] == 2:
print((i+1))
exit()
else:
s = a[s-1]
print((-1))
if __name__=='__main__':
main() | n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
s = 1
for i in range(n):
if a[s-1] == 2:
print((i+1))
exit()
else:
s = a[s-1]
print((-1)) | p03680 |
n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
s = 1
for i in range(n):
if a[s-1] == 2:
print((i+1))
exit()
else:
s = a[s-1]
print((-1)) | def main():
n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
s = 1
for i in range(n):
if a[s-1] == 2:
print((i+1))
exit()
else:
s = a[s-1]
print((-1))
if __name__=='__main__':
main() | p03680 |
n = int(eval(input()))
buttons = [eval(input()) for i in range(n)]
buttons_int = [int(b) - 1 for b in buttons]
button = 0
count = 0
history_list = []
i = 0
while i < n:
if button == i:
button = buttons_int[i]
count += 1
if button == 1:
print(count)
exit()
if i in history_list:
print((-1))
exit()
else:
history_list.append(i)
i = 0
else:
i += 1
| n = int(eval(input()))
buttons = [eval(input()) for i in range(n)]
buttons_int = [int(b) - 1 for b in buttons]
button = 0
for count in range(1, n+1):
button = buttons_int[button]
if button == 1:
print(count)
exit()
print((-1))
| p03680 |
n = int(eval(input()))
a = []
b = []
look = 1
end = 0
count = 0
for i in range(n):
a.append(int(eval(input())))
while end == 0:
count += 1
b.append(look)
look = a[look - 1]
for i in range(len(b)):
if b[i] == look:
end = -1
break
else:
if look == 2:
end = count
print(end) | n = int(eval(input()))
a = []
b = [0]*n
look = 1
end = 0
count = 0
for i in range(n):
a.append(int(eval(input())))
while end == 0:
count += 1
b[look-1] = 1
look = a[look - 1]
if b[look - 1] == 1:
end = -1
else:
if look == 2:
end = count
print(end) | p03680 |
N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
pnext = 1
pvisited = []
while True:
pvisited.append(pnext)
pnext = A[pnext - 1]
if pnext == 2:
print((len(pvisited)))
exit()
if pnext in pvisited:
print((-1))
exit()
| N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
count = 0
pnext = 1
while count < N:
count += 1
pnext = A[pnext - 1]
if pnext == 2:
print(count)
break
else:
print((-1))
| p03680 |
N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
a = []
i = 1
cnt = 0
while i != 2:
a.append(i)
cnt += 1
i = A[i-1]
if i == 2 or i in a:
break
if i == 2:
print(cnt)
else:
print((-1)) | N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
i = 1
cnt = 0
while i != 2 and cnt <= N:
cnt += 1
i = A[i-1]
if i == 2:
break
if i == 2:
print(cnt)
else:
print((-1)) | p03680 |
N = int(eval(input()))
a = [0]
for _ in range(N):
a.append(int(eval(input())))
memo = [1]
next = 1
cnt = 0
while True:
cnt += 1
next = a[next]
if next == 2:
print(cnt)
break
if next in memo:
print((-1))
break
memo.append(next) | N = int(eval(input()))
a = [0]
for _ in range(N):
a.append(int(eval(input())))
memo = [-1] + [1] + [0] * (N-1)
next = 1
cnt = 0
while True:
cnt += 1
next = a[next]
if next == 2:
print(cnt)
break
if memo[next] == 1:
print((-1))
break
memo[next] = 1 | p03680 |
n=int(eval(input()))
s=[0]+[int(eval(input()))for i in range(n)]
p=[1]
k=0
while n:
if s[p[k]]==2:
print((k+1))
break
elif k==len(set(p)):
print((-1))
break
else:
p.append(s[p[k]])
k+=1 | n=int(eval(input()))
s=[0]+[int(eval(input()))for i in range(n)]
t=s[1]
k=1
while n:
if t==2:
print(k)
break
elif t==0:
print((-1))
break
else:
a=s[t]
s[t]=0
t=a
k+=1 | p03680 |
N = int(eval(input()))
a = [int(eval(input())) - 1 for _ in [0]*N]
cur = 0
cnt = -1
for i in range(N):
cur = a[cur]
if cur == 1:
cnt = i + 1
break
print(cnt) | import sys
e = list(map(int,sys.stdin))
cur = e[1]
for i in range(e[0]):
if cur == 2:
print((i + 1))
break
cur = e[cur]
else:
print((-1)) | p03680 |
N = int(eval(input()))
a = {i+1: int(eval(input())) for i in range(N)}
on = 1
ans = -1
count = 0
while True:
on = a[on]
count += 1
if on == 2:
ans = count
break
if on == 1:
break
print(ans)
| N = int(eval(input()))
a = {i+1: int(eval(input())) for i in range(N)}
on = 1
history = {1}
ans = -1
count = 0
while True:
on = a[on]
count += 1
if on == 2:
ans = count
break
if on in history:
break
history.add(on)
print(ans)
| p03680 |
n = int(eval(input()))
a = []
b = 1
c = 1
d = []
for i in range(n):
a.append(int(eval(input())))
while True:
d.append(b-1)
b = a[b-1]
if b == 2:
print(c)
break
if (b-1) in d:
print((-1))
break
c += 1
| n = int(eval(input()))
a = []
for i in range(n):
a.append(int(eval(input())))
k = 1
p = False
for i in range(n):
if a[k-1] == 2:
print((i+1))
p = True
break
k = a[k-1]
if not p:
print((-1))
| p03680 |
N = int(eval(input()))
A = [eval(input()) for i in range(N)]
prev = []
next = 0
count = 0
while(next not in prev and count <= N):
prev.append(next)
next = int(A[next])-1
count += 1
if(next == 1):
print(count)
break
else:
print((-1))
| N = int(eval(input()))
A = [eval(input()) for i in range(N)]
prev = []
next = 0
count = 0
while(count < N):
next = int(A[next])-1
count += 1
if(next == 1):
print(count)
break
else:
print((-1))
| p03680 |
N = int(eval(input()))
a = [set() for _ in range(N)]
for i in range(N):
id = int(eval(input())) - 1
a[id].add(i)
step = -1
already = a[1]
now = a[1]
next = set()
for i in range(N-1):
already = already.union(now)
if 0 in now:
step = i+1
break
for j in now:
next = next.union(a[j])
now = next
next = set()
print(step) | N = int(eval(input()))
a = [set() for _ in range(N)]
for i in range(N):
id = int(eval(input())) - 1
a[id].add(i)
step = -1
#already = a[1]
now = a[1]
next = set()
for i in range(N-1):
#already = already.union(now)
if 0 in now:
step = i+1
break
for j in now:
next = next.union(a[j])
now = next
next = set()
print(step) | p03680 |
N=int(eval(input()))
a=[int(eval(input()))-1 for _ in range(N)]
x=a[0]
ans=1
while x!=0:
if x==1:
print(ans)
break
ans+=1
x=a[x]
else:
print((-1))
| N=int(eval(input()))
a=[int(eval(input()))-1 for _ in range(N)]
x=0
ans=0
while True:
ans+=1
x=a[x]
if x==1:
print(ans)
break
if ans>N:
print((-1))
break;
| p03680 |
N = int(input())
A = [int(input()) for _ in range(N)]
B = [1]
i = 0
flag = False
for _ in range(N):
if 2 in B:
flag = True
break
elif A[i] in B:
break
B.append(A[i])
i = A[i] - 1
print(len(B) - 1) if flag else print(-1)
| N = int(input())
A = [int(input()) for _ in range(N)]
B = [1]
i = 0
cnt = 0
flag = False
for _ in range(N):
i = A[i] - 1
cnt += 1
if i == 1:
flag = True
break
print(cnt) if flag else print(-1)
| p03680 |
N = int(eval(input()))
jmps = []
for _ in range(N):
jmps.append(int(eval(input())) - 1)
now = 0
ans = 0
for i in range(N):
if now == 1:
ans = i
break
now = jmps[now]
ans = ans or -1
print(ans) | N = int(eval(input()))
jmps = [int(eval(input())) - 1 for _ in range(N)]
now = 0
ans = 0
for i in range(N):
if now == 1:
ans = i
break
now = jmps[now]
ans = ans or -1
print(ans)
| p03680 |
N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
L = [0]
i = 0
cnt = 0
while True:
if a[i]-1 == 1:
cnt += 1
break
elif a[i]-1 in L :
cnt = -1
break
else:
L.append(a[i]-1)
cnt += 1
i = a[i]-1
print(cnt) | N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
L = set([0])
i = 0
cnt = 0
while True:
if a[i]-1 == 1:
cnt += 1
break
elif a[i]-1 in L:
cnt = -1
break
else:
L.add(a[i]-1)
cnt += 1
i = a[i]-1
print(cnt) | p03680 |
n = int(eval(input()))
a = [int(eval(input())) for _ in range(n)]
b = [0] * n
ans = 0
c = 0
b[0] = 1
while True:
c = a[c] - 1
ans += 1
if b[c] == 1:
ans = -1
break
if c == 1:
break
print(ans) | n = int(eval(input()))
a = [int(eval(input())) for _ in range(n)]
b = [0] * n
ans = 0
c = 0
b[c] = 1
while True:
c = a[c] - 1
ans += 1
if b[c] == 1:
ans = -1
break
if c == 1:
break
b[c] = 1
print(ans) | p03680 |
import sys
input = lambda: sys.stdin.readline().rstrip()
sys.setrecursionlimit(10**7)
INF = 10**20
def I(): return int(eval(input()))
def F(): return float(eval(input()))
def S(): return eval(input())
def LI(): return [int(x) for x in input().split()]
def LI_(): return [int(x)-1 for x in input().split()]
def LF(): return [float(x) for x in input().split()]
def LS(): return input().split()
def resolve():
N = I()
a = [I() - 1 for _ in range(N)]
c = 0
ans = 0
is_ok = True
while True:
c = a[c]
ans += 1
if c == 0:
is_ok = False
break
if c == 1:
break
if is_ok:
print(ans)
else:
print((-1))
if __name__ == '__main__':
resolve() | import sys
input = lambda: sys.stdin.readline().rstrip()
sys.setrecursionlimit(10**7)
INF = 10**20
def I(): return int(eval(input()))
def F(): return float(eval(input()))
def S(): return eval(input())
def LI(): return [int(x) for x in input().split()]
def LI_(): return [int(x)-1 for x in input().split()]
def LF(): return [float(x) for x in input().split()]
def LS(): return input().split()
def resolve():
N = I()
a = [I() - 1 for _ in range(N)]
c = 0
ans = 0
is_ok = True
while True:
c = a[c]
ans += 1
if c == 0 or ans > N:
is_ok = False
break
if c == 1:
break
if is_ok:
print(ans)
else:
print((-1))
if __name__ == '__main__':
resolve() | p03680 |
N = int(eval(input()))
a = [int(eval(input())) for i in range(N)]
isFound = False
ai = 1
for i in range(1, N + 1):
ai = a[ai - 1]
# print(f'a{i} = {ai}')
if (ai == 2):
isFound = True
print(i)
break
if (isFound is False):
print((-1))
| import sys
N = list(map(int, sys.stdin))
bot = N[1]
for i in range(N[0]):
if bot == 2:
print((i+1))
break
bot = N[bot]
else:
print((-1))
| p03680 |
def main():
n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
check_id=1
check_list=[]
while True:
if check_id in check_list:
print((-1))
break
if check_id==2:
print((len(check_list)))
break
check_list.append(check_id)
check_id=a[check_id-1]
main() | def main():
n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
check_id=1
for i in range(1,n+1):
check_id=a[check_id-1]
if check_id==2:
print(i)
break
if check_id!=2:
print((-1))
main() | p03680 |
import sys
def main():
input = sys.stdin.readline
N = int(eval(input()))
btn = [int(eval(input()))-1 for _ in range(N)]
i = 0
li = [0]
#print(btn)
for _ in range(N):
k = btn[i]
#print(k, li)
if k in li:
print('-1')
break
else:
if k != 1:
li.append(k)
else:
print((len(li)))
break
i = k
if __name__ == '__main__':
main() | import sys
def main():
input = sys.stdin.readline
N = int(eval(input()))
btn = [int(eval(input()))-1 for _ in range(N)]
i = 0
li = [False]*N
#print(btn)
for _ in range(N):
li[i] = True
k = btn[i]
#print(k, li)
if li[k]:
print('-1')
break
elif k == 1:
print((sum(li)))
break
i = k
if __name__ == '__main__':
main() | p03680 |
n = int(eval(input()))
lis = [1]
cou = 0
ans = 0
bo = []
for i in range(n):
bo.append(int(eval(input())))
for i in range(n):
a = bo[cou]
if a not in lis:
lis.append(a)
else:
print("-1")
break
cou = a-1
ans += 1
if a == 2:
print(ans)
break | n = int(eval(input()))
lis = []
p = 1
s = -1
for i in range(n):lis.append(int(eval(input())))
for m in range(n):
p = lis[p-1]
if p == 2:
s = m + 1
break
print(s) | p03680 |
N = int(eval(input()))
A = []
for i in range(N):
A.append(int(eval(input()))-1)
index = 0
count = 0
flag = True
check = []
while flag:
index = A[index]
check.append(index)
count += 1
if len(list(set(check))) != len(check):
flag = False
count = -1
if index == 1:
flag = False
print(count) | N = int(eval(input()))
A = []
for i in range(N):
A.append(int(eval(input()))-1)
index = 0
count = 1
flag = True
while flag:
index = A[index]
if index == 1:
flag = False
else:
count += 1
if count > N:
flag = False
count = -1
print(count) | p03680 |
N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
c = 0
n = 1
while True:
n = A[n-1]
c += 1
if n == 1:
ok = False
break
if n == 2:
ok = True
break
if ok:
print(c)
else:
print((-1)) | N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
c = 0
n = 1
checked = [False for _ in range(N)]
checked[0] = True
for _ in range(N+1):
n = A[n-1]
c += 1
if n == 2:
ok = True
break
if checked[n-1]:
ok = False
break
checked[n-1] = True
if ok:
print(c)
else:
print((-1)) | p03680 |
N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
current = 0
ans = 0
while True:
current = A[current] - 1
ans += 1
if current == 0:
print((-1))
break
if current == 1:
print(ans)
break | N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
current = 0
visited = {0}
ans = 0
while True:
current = A[current] - 1
ans += 1
if current in visited:
print((-1))
break
if current == 1:
print(ans)
break
visited.add(current) | p03680 |
n = int(eval(input()))
a = [int(eval(input())) for _ in range(n)]
ans = 0
visited = set([0])
next_visit_idx = 0
while True:
next_visit_idx = a[next_visit_idx] -1
ans += 1
if next_visit_idx == 1:
print(ans)
break
if next_visit_idx in visited:
print((-1))
break | n = int(eval(input()))
a = [int(eval(input())) for _ in range(n)]
ans = 0
visited = set([0])
next_visit_idx = 0
while True:
next_visit_idx = a[next_visit_idx] -1
ans += 1
if next_visit_idx == 1:
print(ans)
break
if next_visit_idx in visited:
print((-1))
break
visited.add(next_visit_idx) | p03680 |
#coding: utf-8
N = int(eval(input()))
a = []
for i in range(N):
a.append(int(eval(input())))
start = 0
count = 0
for i in range(N):
count += 1
next = a[start]
if(next == 2):
print(count)
break
start = next - 1
else:
print((-1)) | import sys
N = list(map(int, sys.stdin))
bot = N[1]
for i in range(N[0]):
if bot == 2:
print((i+1))
break
bot = N[bot]
else:
print((-1)) | p03680 |
class UFT(object):
def __init__(self,N):
self.par={i:i for i in range(1,N+1)}
self.h={i:0 for i in range(1,N+1)}
def find(self,n):
if self.par[n]==n:
return n
else:
self.par[n]=self.find(self.par[n])
return self.par[n]
def unite(self,a,b):
a=self.find(a)
b=self.find(b)
if self.h[a]>self.h[b]:
self.par[b]=a
else:
self.par[a]=b
if self.h[a]==self.h[b]:
self.h[b]+=1
def issame(self,a,b):
return self.find(a)==self.find(b)
N=int(eval(input()))
obj=UFT(N)
d={i:0 for i in range(1,N+1)}
for i in range(N):
b=int(eval(input()))
d[i+1]=b
obj.unite(i+1,b)
if obj.issame(2,1):
c=1
e=d[1]
while e!=2:
c+=1
e=d[e]
print(c)
else:
print("-1") | n=int(eval(input()))
d={i:int(eval(input())) for i in range(1,n+1)}
f=True
s=1
for i in range(n):
if s==2:
print(i)
f=False
break
s=d[s]
if f:
print((-1)) | p03680 |
N = int(eval(input()))
buttons = [int(eval(input())) for i in range(N)]
visited = [1]
cur = 1
count = 0
for i in range(N):
cur = buttons[cur-1]
count += 1
if cur in visited:
print((-1))
exit()
visited.append(cur)
if cur == 2:
print(count)
exit()
print((-1)) | N = int(eval(input()))
buttons = [int(eval(input())) for i in range(N)]
cur = 1
for i in range(N):
cur = buttons[cur-1]
if cur == 2:
print((i+1))
exit()
print((-1)) | p03680 |
N=int(eval(input()))
a=[int(eval(input())) for i in range(N)]
ans=0
b=1
while(1):
ans+=1
b=a[b-1]
if b==1:
ans=-1
break
if b==2:break
print(ans) | N=int(eval(input()))
a=[int(eval(input())) for i in range(N)]
j=[0]*N
ans=0
b=1
while(1):
ans+=1
b=a[b-1]
j[b-1]+=1
if j[b-1]==2:
ans=-1
break
if b==2:break
print(ans) | p03680 |
n = int(eval(input()))
a = [0] * n
for i in range(n):
a[i] = int(eval(input()))
counter = 0
now = 1
visit = [False] * n
visit[0] = True
while True:
counter += 1
if a[now - 1] == 2:
print(counter)
break
elif visit[a[now - 1]-1] == True:
print((-1))
break
else:
visit[a[now - 1]-1] = True
now = a[now - 1]
| n = int(eval(input()))
a = [0] * n
for i in range(n):
a[i] = int(eval(input()))
visit = set()
now = 1
for i in range(1, n + 10):
if now not in visit:
visit.add(now)
now = a[now - 1]
else:
print((-1))
break
if now == 2:
print(i)
break
| p03680 |
N = int(eval(input()))
dic = {}
for n in range(1,N+1):
dic[n] = int(eval(input()))
lis = []
now = 1
count = 0
flag = False
while True:
#count += 1
if now in lis:
break
if dic[now] == 2:
flag = True
break
lis.append(now)
now = dic[now]
if flag:
print((len(lis)+1))
else:
print((-1)) | N = int(eval(input()))
dic = {}
for n in range(1,N+1):
dic[n] = int(eval(input()))
now = 1
count = 0
flag = False
while True:
if now==2:
flag = True
break
if now not in dic:
break
now = dic.pop(now)
#del dic[now]
count += 1
if flag:
print(count)
else:
print((-1)) | p03680 |
n = int(eval(input()))
li = [int(eval(input())) for _ in range(n)]
cnt = 0
liuse = [1]
place = 1
for i in range(n):
place = li[place-1]
liuse.append(place)
cnt += 1
if place == 2:
print(cnt)
exit()
if len(liuse) > len(set(liuse)):
print((-1))
exit() | n = int(eval(input()))
li = [int(eval(input())) for _ in range(n)]
liuse = [0]*n
liuse[0] = 1
for i in range(1,n):
liuse[i] = li[liuse[i-1]-1]
if 2 in liuse:
print((liuse.index(2)))
else:
print((-1)) | p03680 |
n=int(eval(input()))
a=[]
b=[]
for i in range(n):
a.append(int(eval(input())))
next=0
count=0
while next!=1:
if a[next]-1 in b:
count=-1
break
b.append(a[next]-1)
next=a[next]-1
count+=1
print(count)
| n=int(eval(input()))
a = [int(eval(input())) for _ in range(n)]
b=[]
next=0
count=0
for i in range(n):
next=a[next]-1
count+=1
if next==1:
print(count)
exit()
print((-1))
| p03680 |
n=int(eval(input()))
a=[]
for i in range(n):
a.append(int(eval(input())))
i=0
count=1
while(1):
if a[i]==1:
frag=-1
break
elif a[i]==2:
frag=count
break
else:
i=a[i]-1
count+=1
print(frag) | n=int(eval(input()))
a=[]
for i in range(n):
a.append(int(eval(input())))
i=0
count=1
frag=-1
for j in range(n):
if a[i]==2:
frag=count
break
else:
i=a[i]-1
count+=1
print(frag) | p03680 |
n = int(eval(input()))
A = [int(eval(input())) for _ in range(n)]
sec = []
count, cur = 0, 1
while cur not in sec:
sec.append(cur)
if cur == 2:
break
cur = A[cur - 1]
count += 1
print((count if 2 in sec else -1)) | n = int(eval(input()))
A = [int(eval(input())) for _ in range(n)]
count, current = 0, 1
while current != 2:
current = A[current - 1]
count += 1
if count > n:
count = -1
break
print(count) | p03680 |
# ABC 65 B
def resolve():
N = int(eval(input()))
a = [0] * (N+1)
for i in range(N):
a[i+1] = int(eval(input()))
b = 1
ans = 0
while (True):
tmp = a[b]
a[b] = 0
b = tmp
ans += 1
if b == 2:
print(ans)
return
elif b == 0:
print((-1))
return
print((-1))
return
if __name__ == "__main__":
resolve()
| def resolve():
n = int(eval(input()))
a = []
for i in range(n):
a.append(int(eval(input())) - 1)
ans = 0
idx = 0
while True:
if a[idx] == -1:
print("-1")
return
if idx == 1:
break
ans += 1
tmp = a[idx]
a[idx] = -1
idx = tmp
print(ans)
return
if __name__ == "__main__":
resolve()
| p03680 |
n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
ans = 0
i = 0
while n > 0:
ans += 1
if a[i] == 2:
print(ans)
quit()
else:
i = a[i]-1
n -= 1
print((-1))
| n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
ans = -1
next_a = a[0]
for i in range(1, n):
if next_a == 2:
ans = i
print(ans)
quit()
next_a = a[next_a-1]
print(ans)
| p03680 |
def solve():
a = read()
result = think(a)
write(result)
def read():
n = read_int(1)[0]
a = []
for _ in range(n):
a.append(read_int(1)[0])
return a
def read_int(n):
return list([int(x) for x in read_line().split(' ')])[:n]
def read_line(n=0):
if n == 0:
return input().rstrip()
else:
return input().rstrip()[:n]
def think(a):
dummy = -1
buttons_flash_info = list(a)
buttons_flash_info.insert(0, dummy)
index = 1
visited = set()
visited.add(index)
push_count = 1
while True:
next_index = buttons_flash_info[index]
index = next_index
if index == 2:
return push_count
if index in visited:
return -1
push_count += 1
return -1
def write(result):
print(result)
if __name__ == '__main__':
solve() | def solve():
a = read()
result = think(a)
write(result)
def read():
n = read_int(1)[0]
a = []
for _ in range(n):
a.append(read_int(1)[0])
return a
def read_int(n):
return list([int(x) for x in read_line().split(' ')])[:n]
def read_line(n=0):
if n == 0:
return input().rstrip()
else:
return input().rstrip()[:n]
def think(a):
dummy = -1
flag_for_not_visited = 0
flag_for_visited = 1
buttons_flash_info = list(a)
buttons_flash_info.insert(0, dummy)
index = 1
visited = [flag_for_not_visited for i in range(len(buttons_flash_info))]
visited[index] = flag_for_visited
push_count = 1
while True:
next_index = buttons_flash_info[index]
index = next_index
if index == 2:
return push_count
if visited[index] == flag_for_visited:
return -1
visited[index] = flag_for_visited
push_count += 1
return -1
def write(result):
print(result)
if __name__ == '__main__':
solve() | p03680 |
# coding: utf-8
N = int(eval(input()))
pushed = []
button = [0] * (N + 1)
for i in range(1, N+1):
button[i] = int(eval(input()))
push_button = 1
for _ in range(1, N+1):
if push_button in pushed:
print("-1")
exit(0)
elif push_button == 2:
print((len(pushed)))
exit(0)
else:
pushed.append(push_button)
push_button = button[push_button]
| # coding: utf-8
N = int(eval(input()))
pushed = []
button = [0] * (N + 1)
for i in range(1, N+1):
button[i] = int(eval(input()))
push_button = 1
for _ in range(1, N+1):
if push_button == 2:
print((len(pushed)))
exit(0)
else:
pushed.append(push_button)
push_button = button[push_button]
print("-1")
| p03680 |
n=int(eval(input()))
a=[]
cnt=0
now=0
for i in range(n):
a.append(int(eval(input()))-1)
flg=False
for i in range(n):
if now==1:
flg=True
break
now=a[now]
cnt+=1
print((cnt if flg else -1)) | N,*a = list(map(int,open(0).read().split()))
a.insert(0,0)
flg = False
on = 1
cnt = 0
for i in range(N):
on = a[on]
cnt += 1
if on == 2:
print(cnt)
exit()
print((-1)) | p03680 |
n = int(eval(input()))
A = [int(eval(input())) for i in range(n)]
M = [1]
i = 1
while True:
M.append(A[i-1])
i = A[i-1]
if 2 in M:
print((len(M)-1))
break
else:
for j in range(len(M)):
if M.count(M[j]) > 1:
print("-1")
exit()
| n = int(eval(input()))
A = [int(eval(input())) for i in range(n)]
A = [0] + A
count = 0
light = 1
if 2 not in A:
print("-1")
exit()
else:
while light != 2 and count <= n:
count += 1
light = A[light] #A = [0] + Aとしているので，これでよい．light-1としなくてよい．
if count <= n:
print(count)
else:
print("-1") | p03680 |
N = int(eval(input()))
a = [int(eval(input())) for i in range(N)]
now = a[0]
count = 1
c = 0
for i in range(10**6):
if now != 2:
count += 1
now = a[now - 1]
else:
print(count)
c = 1
break
if c == 0:
print((-1))
| N = int(eval(input()))
a = [0] + [int(eval(input())) for _ in range(N)]
x = 1
visited = set([1])
answer = 0
while True:
x = a[x]
if x in visited:
answer = -1
break
visited.add(x)
answer += 1
if x == 2:
break
print(answer)
| p03680 |
N = int(eval(input()))
A = [int(eval(input()))-1 for _ in range(N)]
done = []
light = 0
flag = 0
ans = -1
cnt = 0
while flag == 0:
done.append(light)
light = A[light]
cnt += 1
if light == 1:
ans = cnt
flag = 1
if light in done:
flag = 1
print(ans) | N = int(eval(input()))
A = [int(eval(input()))-1 for _ in range(N)]
light = 0
ans = -1
for n in range(1,N+1):
light = A[light]
if light ==1:
ans = n
break
print(ans) | p03680 |
N = eval(input())
arr = [eval(input())-1 for i in range(N)]
now = 0
count = 0
while (now != 1):
count += 1
now = arr[now]
if count > 100000:
count = -1
break
print(count)
| N = int(eval(input()))
src = [int(eval(input())) for i in range(N)]
now = 0
for i in range(N):
a = src[now] - 1
if a == 1:
print((i+1))
exit()
now = a
print((-1)) | p03680 |
N = int(eval(input()))
src = [int(eval(input())) for i in range(N)]
now = 0
for i in range(N):
a = src[now] - 1
if a == 1:
print((i+1))
exit()
now = a
print((-1)) | N = int(eval(input()))
src = [int(eval(input())) for i in range(N)]
now = src[0] - 1
for i in range(N):
if now == 1:
print((i+1))
exit()
now = src[now] - 1
print((-1)) | p03680 |
N = int(eval(input()))
a = list(int(eval(input())) for i in range(N))
tmp = 1
for i in range(N):
tmp = a[tmp-1]
if tmp == 2:
print((i + 1))
exit()
print((-1)) | N = int(eval(input()))
a = [0] * N
for i in range(N):
a[i] = int(eval(input()))
tmp = 1
for i in range(N):
tmp = a[tmp-1]
if tmp == 2:
print((i + 1))
exit()
print((-1)) | p03680 |
n = int(eval(input()))
a = []
hist = []
for i in range(n):
a.append(int(eval(input())))
pos = 1
count = 0
while True:
if pos == 2:
print(count)
break
if pos in hist:
print((-1))
break
hist.append(pos)
pos = a[pos-1]
count += 1 | N = int(eval(input()))
a = [int(eval(input())) for i in range(N)]
ans = 0
turn = 1
while True:
if a[turn-1] == 2:
ans += 1
break
if a[turn-1] == 0:
ans = -1
break
next_turn = a[turn-1]
a[turn-1] = 0
ans += 1
turn = next_turn
print(ans) | p03680 |
n=int(eval(input()))
l=[int(eval(input())) for i in range(n)]
a=1
ans=0
while a!=2:
a=l[a-1]
ans+=1
if a==1:
ans=-1
break
print(ans)
| n=int(eval(input()))
l=[int(eval(input())) for i in range(n)]
a=1
ans=0
while a!=2:
a=l[a-1]
ans+=1
if ans==n+1:
ans=-1
break
print(ans)
| p03680 |
n = int(eval(input()))
lst = [int(eval(input())) for _ in range(n)]
blst = []
i = 1
n = 0
while i not in blst:
blst.append(i)
i = lst[i - 1]
n += 1
if i == 2:
print(n)
quit()
print((-1)) | n = int(eval(input()))
lst = [int(eval(input())) for _ in range(n)]
i = 1
c = 0
for _ in range(n):
i = lst[i - 1]
c += 1
if i == 2:
print(c)
quit()
print((-1)) | p03680 |
n = int(eval(input()))
lst = [int(eval(input())) for _ in range(n)]
i = 1
c = 0
for _ in range(n):
i = lst[i - 1]
c += 1
if i == 2:
print(c)
quit()
print((-1)) | n = int(eval(input()))
lst = [int(eval(input())) for _ in range(n)]
i = 1
for c in range(n):
i = lst[i - 1]
if i == 2:
print((c + 1))
quit()
print((-1)) | p03680 |
n = int(eval(input()))
lst = [int(eval(input())) for _ in range(n)]
i = lst[0]
for c in range(n):
if i == 2:
print((c + 1))
quit()
i = lst[i - 1]
print((-1)) | import sys
n = int(eval(input()))
lst = [int(i) for i in sys.stdin]
i = lst[0]
for c in range(n):
if i == 2:
print((c + 1))
quit()
i = lst[i - 1]
print((-1)) | p03680 |
N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
pushed = [False] * N
pushed[0] = True
button = 0
count = 0
while True:
count += 1
button = A[button] - 1
if button == 1:
print(count)
exit()
if pushed[button]:
print((-1))
exit()
| N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
pushed = [False] * N
pushed[0] = True
button = 0
count = 0
while True:
count += 1
button = A[button] - 1
if button == 1:
print(count)
exit()
if pushed[button]:
print((-1))
exit()
pushed[button] = True | p03680 |
import sys;sys.setrecursionlimit(9**9);*A,=list(map(int,open(0)))
def f(i,t):
if i==2:return len(t)
if i in t:return -1
return f(A[i],t+[i])
print((f(1,[]))) | *A,=list(map(int,open(0)));i=1;t=[0]*A[0]+[0]
while i-2and t[i]==0:t[i]=1;i=A[i]
print((-1if i-2else sum(t))) | p03680 |
import sys
N = int(eval(input()))
a = [int(eval(input())) for i in range(N)]
d = [0]
b = 0
c = 0
while True:
if b == 1:
print(c)
sys.exit()
c += 1
b = a[b] - 1
if b in d:
print('-1')
sys.exit()
d.append(b) | import sys
N = int(eval(input()))
a = [int(eval(input())) for i in range(N)]
d = [0] * N
b = 0
c = 0
while True:
if b == 1:
print(c)
sys.exit()
c += 1
b = a[b] - 1
if d[b] == 1:
print('-1')
sys.exit()
d[b] = 1
| p03680 |
import sys
N = int(eval(input()))
a = [int(eval(input())) for i in range(N)]
d = [0] * N
b = 0
c = 0
while True:
if b == 1:
print(c)
sys.exit()
c += 1
b = a[b] - 1
if d[b] == 1:
print('-1')
sys.exit()
d[b] = 1
| N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
s = [0] * N
c = 0
OK = False
n = 0
while True:
c += 1
n = a[n] - 1
if n == 1:
OK = True
break
if s[n] == 1:
break
s[n] = 1
if OK:
print(c)
else:
print((-1)) | p03680 |
n=int(eval(input()))
a=[int(eval(input())) for _ in range(n)]
cnt=0
tmp=1
already=[]
while True:
cnt+=1
already.append(tmp)
tmp=a[tmp-1]
if tmp==2:
print(cnt)
break
elif tmp in already[::-1]:
print((-1))
break | import sys
n=int(eval(input()))
a=[int(eval(input())) for _ in range(n)]
cnt=0
tmp=1
for i in range(n):
cnt+=1
tmp=a[tmp-1]
if tmp==2:
print(cnt)
sys.exit()
print((-1)) | p03680 |
N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
count = 0
i = 1
osita = []
while 2 not in osita:
osita.append(i)
i = a[i-1]
count += 1
if count > len(a):
print((-1))
exit()
print((count-1)) | N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
count = 0
i = 1
x = 0
osita = [0]*(N+1)
for b in range(N+1):
osita[b] = i
i = a[i-1]
if 2 in osita:
print((osita.index(2)))
else:
print((-1)) | p03680 |
import sys
l = [int(i) for i in sys.stdin]
N = l[0]
a = [int(i) - 1 for i in l[1:]]
done = [False] * N
i = 0
ans = 0
while True:
if done[i] == False:
done[i] = True
ans += 1
if a[i] == 1:
break
i = a[i]
else:
ans = -1
break
print(ans)
| import sys
l = [int(i) - 1 for i in sys.stdin]
N = l[0] + 1
a = l[1:]
done = [False] * N
i = 0
ans = 0
while True:
if done[i] == False:
done[i] = True
ans += 1
if a[i] == 1:
break
i = a[i]
else:
ans = -1
break
print(ans)
| p03680 |
n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
on = 1
count = 0
on_li = [1]
while True:
on = a[on-1]
count += 1
if on == 2:
print(count)
exit()
if on in on_li:
print((-1))
exit()
else:
on_li.append(on) | n=int(eval(input()))
a=[int(eval(input())) for i in range(n)]
c,s=1,a[0]
while s!=2 and c<n:
c,s=c+1,a[s-1]
print((c if c<n else -1))
| p03680 |
n = int(eval(input()))
table = {}
for i in range(n):
a = int(eval(input()))
table[i] = a-1
is_visited = [ False for _ in range(n) ]
is_visited[0] = True
cnt = 0
now = 0
while True:
if now == 1:
print(cnt)
break
nxt = table[now]
if is_visited[nxt]:
print((-1))
break
now = nxt
cnt += 1 | n = int(eval(input()))
table = {}
for i in range(n):
a = int(eval(input()))
table[i] = a-1
is_visited = [ False for _ in range(n) ]
is_visited[0] = True
cnt = 0
now = 0
while True:
is_visited[now] = True
if now == 1:
print(cnt)
break
nxt = table[now]
if is_visited[nxt]:
print((-1))
break
now = nxt
cnt += 1 | p03680 |
n = int(eval(input()))
btn = []
checked = []
flag = True
for i in range(n):
btn.append(int(eval(input())))
def find(n):
global btn, checked
j = 1
count = 0
for i in range(n):
if btn[j - 1] == 2:
count += 1
return count
elif j - 1 in checked:
return -1
else:
checked.append(j - 1)
j = btn[j - 1]
count += 1
return -1
print((find(n))) | n = int(eval(input()))
btn = []
checked = set()
for i in range(n):
btn.append(int(eval(input())))
def find(n):
global btn, checked
j = 1
for i in range(n):
if btn[j - 1] == 2:
# count += 1
return len(checked) + 1
elif j - 1 in checked:
return -1
else:
checked.add(j - 1)
j = btn[j - 1]
return -1
print((find(n))) | p03680 |
n = int(eval(input()))
a = [0] + [int(eval(input())) for i in range(n)]
end = {}
end[1] = True
to = a[1]
cnt = 0
while True:
cnt += 1
if to == 2:
print(cnt)
__import__("sys").exit()
if end.get(to) == None:
to = a[to]
else:
break
print((-1))
| n = int(eval(input()))
a = [0] + [int(eval(input())) for i in range(n)]
end = {}
end[1] = True
to = a[1]
cnt = 0
while True:
cnt += 1
if to == 2:
print(cnt)
__import__("sys").exit()
if end.get(to) == None:
end[to] = True
to = a[to]
else:
break
print((-1))
| p03680 |
n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
i = 1
count = 0
while True:
i = a[i-1]
count += 1
if i == 1:
print((-1))
break
elif i == 2:
print(count)
break | n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
i = 1
count = 0
while True:
i = a[i-1]
count += 1
if i == 1 or count == n+1:
print((-1))
break
elif i == 2:
print(count)
break | p03680 |
n=int(eval(input()))
lst=[int(eval(input())) for i in range(n)]
lst = list([x-1 for x in lst])
counts = 0
lst_p = [0]
tmp = 0
while True:
tmp = lst[tmp]
counts += 1
if tmp == 1:
print(counts)
break
if tmp in lst_p:
print((-1))
break
lst_p.append(tmp) | n=int(eval(input()))
lst=[int(eval(input())) for i in range(n)]
lst = list([x-1 for x in lst])
lst_p = [0]
tmp = 0
flag =True
for i in range(n+1):
tmp = lst[tmp]
if tmp == 1:
print((i+1))
flag = False
break
if flag:
print((-1)) | p03680 |
N = int(eval(input()))
a = []
for _ in range(N):
a.append(int(eval(input())))
ans = 1
button = a[0]
for i in range(N):
if button == 2:
break
button = a[button-1]
ans += 1
if ans >= N+1:
print((-1))
else:
print(ans) | N = int(eval(input()))
a = []
for _ in range(N):
a.append(int(eval(input()))-1)
tmp = a[0]
ans = 1
for i in range(N+1):
if tmp == 1:
print(ans)
break
tmp = a[tmp]
ans += 1
else:
print((-1)) | p03680 |
n = eval(input())
b = []
b_old = []
for i in range(int(n)):
tmp = eval(input())
b.append(int(tmp))
count = 1
s = b[0]
if s == 2:
print(count)
else:
b_old.append(s)
n_b = s
flag = 0
while(True):
count += 1
n_b = b[n_b-1]
if n_b == 2:
print(count)
flag = 1
break
elif n_b in b_old:
print("-1")
flag = 1
break
elif count == int(n):
print("-1")
break
else:
b_old.append(n_b)
| n = int(eval(input()))
b = []
b_old = []
for i in range(n):
tmp = int(eval(input()))
b.append(tmp)
n_b = 1
count = 0
flag = 0
while(count < n):
n_b = b[n_b-1]
count += 1
if n_b == 2:
print(count)
flag = 1
break
if flag == 0:
print("-1")
| p03680 |
n = int(eval(input()))
a = []
for i in range(n):
a.append(int(eval(input())))
past = [0 for _ in range(n)]
cnt = 0
now = 1
while(True):
if past[now-1] == 1:
print((-1))
exit(0)
if now == 2:
print(cnt)
exit(0)
past[now-1] = 1
cnt += 1
now = a[now-1] | n = int(eval(input()))
inp = [int(eval(input())) for i in range(n)]
checked = [0 for _ in range(n)]
cnt = 0
light = 0
while(True):
if checked[light]:
print((-1))
break
checked[light] = True
light = inp[light] - 1
cnt += 1
if light == 1:
print(cnt)
break
| p03680 |
N = int(eval(input()))
a = [int(eval(input())) for _ in range(N) ]
hist = [1]
bottun = 0
i = 0
while True:
# print(hist)
bottun = a[hist[i]-1]
# print(bottun)
for j in hist:
if bottun == j:
print((-1))
# print("hoge")
exit()
if bottun == 2:
print((len(hist)))
exit()
hist.append(bottun)
i += 1
| N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
hist = [0] * N
bottun = a[0]
cnt = 1
hist[0] = 1
while True:
# print(hist)
# print(bottun)
if hist[bottun-1] == 1:
print((-1))
exit()
if bottun == 2:
print(cnt)
exit()
hist[bottun-1] = 1
bottun = a[bottun-1]
cnt += 1
| p03680 |
N = int(eval(input()))
a = tuple(int(eval(input())) for _ in range(N))
log = set()
i = 0
count = 1
while a[i] != 2:
i = a[i] - 1
if i in log:
print((-1))
break
else:
log.add(i)
count += 1
else:
print(count) | N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
log = set()
i = 0
count = 1
while a[i] != 2:
i = a[i] - 1
if i in log:
print((-1))
break
else:
log.add(i)
count += 1
else:
print(count) | p03680 |
N = int(eval(input()))
a_lis = [int(eval(input())) for _ in range(N)]
now = 1
flag = 1
memo = []
cnt = 0
for i in range(N):
next = a_lis[now-1]
if next in memo:
print((-1))
flag = 0
break
else:
memo.append(next)
now = next
cnt+=1
if next ==2:
print(cnt)
break
| N = int(eval(input()))
a_lis = [int(eval(input())) for _ in range(N)]
now = 1
flag = 1
cnt = 0
while cnt<N and next!=2:
cnt+=1
next = a_lis[now-1]
now = next
if next==2:print(cnt)
else:print((-1))
| p03680 |
import sys
n=int(eval(input()))
a=[]
for i in range(n):
a.append(int(eval(input())))
count =1 #ボタンを押した回数用
s=0 #スタートするボタン これを操作ボタンにしていく
while True:
if a[s]==2:
print(count)
sys.exit()
elif count>1 and s==0:
print((-1))
sys.exit()
else:
count+=1
s=a[s]-1
| import sys
n=int(eval(input()))
a=[]
for i in range(n):
a.append(int(eval(input())))
count =1 #ボタンを押した回数用
s=0 #スタートするボタン これを操作ボタンにしていく
while True:
if a[s]==2:
print(count)
sys.exit()
elif count>n:
print((-1))
sys.exit()
else:
count+=1
s=a[s]-1
| p03680 |
N = int(eval(input()))
a = []
for i in range(N):
a.append(int(eval(input())))
pushed = [0] * N
pushed[0] = 1
current_bottom = a[0]
ans = 1
if current_bottom == 2:
print(ans)
exit()
for _ in range(N):
current_bottom = a[current_bottom-1]
if pushed[current_bottom-1] == 1:
print((-1))
exit()
else:
pushed[current_bottom-1] = 1
ans += 1
if current_bottom == 2:
print(ans)
exit() | N = int(eval(input()))
a = []
for i in range(N):
a.append(int(eval(input())))
current_bottom = a[0]
ans = 1
if current_bottom == 2:
print(ans)
exit()
for _ in range(N):
current_bottom = a[current_bottom-1]
ans += 1
if current_bottom == 2:
print(ans)
exit()
print((-1)) | p03680 |
n = int(eval(input()))
a = [int(eval(input())) for _ in range(n)]
count = 0
visited = []
ans = -1
btn = 0
for _ in range(n):
if btn in visited:
break
visited.append(btn)
btn = a[btn]-1
count += 1
if btn==1:
ans = count
break
print(ans)
| n = int(eval(input()))
a = [int(eval(input())) for _ in range(n)]
ans = -1
count = 0
btn = 0
for i in range(n):
btn = a[btn]-1
count += 1
if btn == 1:
ans = count
break
print(ans)
| p03680 |
N=int(eval(input()))
A=[]
for i in range(N):
A.append(int(eval(input())))
light=1
count=0
while True:
if light==2:
print(count)
quit()
elif count>0 and light==1:
print((-1))
quit()
else:
light=A[light-1]
count+=1 | N=int(eval(input()))
A=[]
for i in range(N):
A.append(int(eval(input())))
light=1
count=0
for i in range(N):
if light==2:
print(count)
quit()
elif count>0 and light==1:
print((-1))
quit()
else:
light=A[light-1]
count+=1
print((-1))
| p03680 |
n=int(eval(input()))
a=[int(eval(input())) for i in range(n)]
b=a[0]
cnt=1
while b!=2:
b=a[b-1]
cnt+=1
if b==a[0]:
print((-1))
exit()
print(cnt)
| n=int(eval(input()))
a=[int(eval(input())) for i in range(n)]
b=a[0]
cnt=1
if b==2:
print(cnt)
else:
while cnt<=n+2:
b=a[b-1]
cnt+=1
if b==2:
print(cnt)
exit()
print((-1))
| p03680 |
n = int(eval(input()))
A = [int(eval(input())) for i in range(n)]
ans = 1
light = 0
list = []
while True:
if A[light] in list:
ans = -1
break
elif A[light] == 2:
break
else:
ans = ans + 1
list.append(light + 1)
light = A[light] - 1
print(ans) | n = int(eval(input()))
A = [int(eval(input())) for i in range(n)]
ans = 0
light = 1
list = [0] * n
while True:
if light == 2:
break
elif list[light - 1] == 1:
ans = -1
break
else:
ans = ans + 1
list[light - 1] = 1
light = A[light - 1]
print(ans) | p03680 |
N = int(eval(input()))
A = {i+1: int(eval(input())) for i in range(N)}
v = 1
for cnt in range(N):
v = A[v]
if(v == 2):
print((cnt+1))
break
else:
print((-1)) | N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
b = 0
for i in range(N):
if(b != 0):
b -=1
b = A[b]
if(b == 2):
print((i+1))
break
else:
print((-1)) | p03680 |
# -*- coding:utf-8 -*-
import sys
l = [int(i) for i in sys.stdin]
used = []
add = used.append
now = 1
count = 0
while True:
if now == 2:
break
if now in used:
print((-1))
exit()
add(now)
now = l[now]
count += 1
print(count) | # -*- coding:utf-8 -*-
import sys
button = [int(i) for i in sys.stdin]
now = 1
count = 0
for i in range(button[0]):
if now == 2:
print(count)
exit()
now = button[now]
count += 1
print((-1)) | p03680 |
n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
j = 0
for k in range(n):
j = a[j] - 1
if j == 1:
print((k+1))
break
elif k == n-1:
print((-1))
else:
pass | n = int(eval(input()))
a = [int(eval(input())) for i in range(n)]
j = 0
for k in range(n):
j = a[j] - 1
if j == 1:
print((k+1))
break
else:
pass
else:
print((-1)) | p03680 |
N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
pikaa = 1
ans = 0
while 1:
pikaa = a[pikaa - 1]
ans += 1
if pikaa == 1:
print((-1))
exit()
elif pikaa == 2:
print(ans)
exit()
| N = int(eval(input()))
a = [int(eval(input())) for _ in range(N)]
pikaa = 1
ans = 0
for _ in range(N):
pikaa = a[pikaa - 1]
ans += 1
if pikaa == 2:
print(ans)
exit()
print((-1))
| p03680 |
n = int(eval(input()))
a = [int(eval(input())) - 1 for _ in range(n)]
i = 0
count = 0
pushed = []
while(1):
pushed.append(i)
i = a[i]
count += 1
if i == 1:
break
elif i in pushed:
count = -1
break
print(count) | n = int(eval(input()))
a = [int(eval(input())) - 1 for _ in range(n)]
i = 0
count = 0
for _ in range(n+1):
i = a[i]
count += 1
if i == 1:
break
if count == n + 1:
count = -1
print(count) | p03680 |
import sys
n = int(eval(input()))
a = []
for i in range(n):
a.append(int(eval(input())))
cnt = 0
t = 1
for i in a:
t = a[t-1]
cnt += 1
if t == 2:
print(cnt)
sys.exit()
print("-1")
| N = int(eval(input()))
A = [int(eval(input())) for _ in range(N)]
cnt = 0
tmp = 1
for i in A:
tmp = A[tmp-1]
cnt += 1
if tmp == 2:
print(cnt)
exit()
print("-1")
| p03680 |
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