205. Isomorphic Strings
题目：
https://leetcode.com/problems/isomorphic-strings/
难度 : Easy
AC之法，用dictionary，因为限制，所以确保s 和 t 是isomorphic 同时 t 和 s 是
class Solution(object):
def isIsomorphic(self, s, t):
"""
:type s: str
:type t: str
:rtype: bool
"""
return self.iso(s,t) and self.iso(t,s)
def iso(self,s, t):
"""
:type s: str
:type t: str
:rtype: bool
"""
mapx = {}
for i in range(len(s)):
if s[i] not in mapx:
mapx[s[i]] = t[i]
elif s[i] in mapx:
if t[i] != mapx[s[i]]:
return False
return True
