Untitled
123456789101112131415
def ans(A):
w = set() # walked
res = 0 # result
for a in A:
c = 0 # count
while a not in w:
w.add(a)
c += 1
a = A[a]
res = max(res, c)
print(res)
# 0 1 2 3 4 5 6 7 8 9
ans([5,4,0,3,1,2])
ans([5,4,0,3,1,2,9,6,7,8])
Python
INFO