LeetCode:Isomorphic Strings

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<char,char> datamap;
        for(int i=0;i<s.size();i++)
        {
           if(datamap.find(s[i])==datamap.end()) 
                datamap[s[i]]=t[i];
           else if(datamap[s[i]]!=t[i])
                return false;
        }
        datamap.clear();
       
        for(int i=0;i<t.size();i++)
        {
           if(datamap.find(t[i])==datamap.end()) 
                datamap[t[i]]=s[i];
           else if(datamap[t[i]]!=s[i])
                return false;
        }
        
    }
};