https://www.hackerrank.com/challenges/no-prefix-set

no-prefix-set.py

# This is done! 
size = int(raw_input())
def node():
  return [0, {}, 0]
words = node()
ans = 1
for s in xrange(size):
  if not ans: break
  word = str(raw_input())
  root = words
  for chr in word:
    root[0] = 1
    if root[2]:
        ans = 0
        break
    if not root[1].get(chr):
        root[1][chr] = node()
    root = root[1].get(chr)
  if root[0]:
    ans = 0
  else:
    root[0] = 1
    root[2] = 1
if ans:
    print 'GOOD SET'
else:
    print 'BAD SET'
    print word