[leetcode]205. Isomorphic Strings
Given two strings s and t, determine if they are isomorphic.
Two strings are isomorphic if the characters in s can be replaced to get t.
All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character but a character may map to itself.
For example,
Given "egg", "add", return true.
Given "foo", "bar", return false.
Given "paper", "title", return true
判断两个字符串是否同构，即s中的每个字符是否可以和t中的字符一一对应，每个字符只能对应除了自身外唯一的值
解法1：
1 class Solution(object): 2 def isIsomorphic(self, s, t): 3 return [s.find(i) for i in s] == [t.find(i) for i in t]
解法2：
1 class Solution(object): 2 def isIsomorphic(self, s, t): 3 return map(s.find,s) == map(t.find,t)
解法3：
1 class Solution(object): 2 def isIsomorphic(self, s, t): 3 return len(set(zip(s,t))) == len(set(s)) == len(set(t))
解法4：
1 class Solution(object): 2 def isIsomorphic(self, s, t): 3 ds = collections.defaultdict(list) 4 dt = collections.defaultdict(list) 5 for i,c in enumerate(s): 6 ds[c].append(i) 7 for i,c in enumerate(t): 8 dt[c].append(i) 9 return sorted(ds.values())==sorted(dt.values())
