290. Word Pattern

class Solution {public:    bool wordPattern(string pattern, string str) {        map<char, string> c2sm;        map<string, char> s2cm;        stringstream ss(str);                string s;            for(int i = 0; i < pattern.size(); ++i){            if(ss.eof())                return false;            ss>>s;            if(c2sm.find(pattern[i]) == c2sm.end()){                c2sm[pattern[i]] = s;            }            else{                if(c2sm[pattern[i]] != s)                    return false;            }            if(s2cm.find(s) == s2cm.end()){                s2cm[s] = pattern[i];            }            else{                if(s2cm[s] != pattern[i])                    return false;            }                    }                if(!ss.eof())            return false;        return true;    }};