1079.py

'''
You have a set of tiles, where each tile has one letter tiles[i] printed on it. Return the number of possible non-empty sequences of letters you can make.



Example 1:

Input: "AAB"
Output: 8
Explanation: The possible sequences are "A", "B", "AA", "AB", "BA", "AAB", "ABA", "BAA".
Example 2:

Input: "AAABBC"
Output: 188
'''

classSolution(object):
defnumTilePossibilities(self, tiles):
"""
 :type tiles: str
 :rtype: int
 """

ifnottiles:
return0

importcollections
unique=set(tiles)
freq_map=collections.Counter(tiles)
total_len=1
whiletotal_len<len(tiles):
new=set()
forcharintiles:
forcombinunique:
new_seq=comb+char
up_freq=collections.Counter(new_seq)
flag=True
forkey, valinup_freq.items():
ifval>freq_map[key]:
flag=False
ifflag:
new.add(new_seq)
# print new
unique.update(new)

total_len+=1
returnlen(unique)