problem:

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.

solution:这道题木实则判断两个字符串是否为同构字符串。只要保证s t 互相都映射成功，用unordered_map 来记录它们之间的相互映射

class Solution {public:    bool isIsomorphic(string s, string t) {        if(s.size()!=t.size())            return false;                    unordered_map
     
       datamap;        for(int i=0;i