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.

Note: You may assume both s and t have the same length.

class Solution(object):
    def isIsomorphic(self, s, t):
        """
        :type s: str
        :type t: str
        :rtype: bool
        """
        d1, d2 = {}, {}
        for i, v in enumerate(s):
            d1[v] = d1.get(v,[]) + [i]
        for i, v in enumerate(t):
            d2[v] = d2.get(v,[]) + [i]
        return sorted(d1.values()) == sorted(d2.values())

Trick:

class Solution(object):
    def isIsomorphic(self, s, t):
        """
        :type s: str
        :type t: str
        :rtype: bool
        """
        return map(s.find, s) == map(t.find, t)