网易4.21第二题：dfs
def dfs(n):
if n == 1: return 1
if v[fa[n-2]-1] < v[n-1]:
return dfs(fa[n-2])
else:
return n
res = [1]
for i in range(n-1):
res.append(dfs(i+2))
print(' '.join([str(i) for i in res]))
