290.cpp

class Solution {
public:
    bool wordPattern(string pattern, string str) {
        str += ' ';
        int i = 0, j = 0, len1 = pattern.size(), len2 = str.size();
        unordered_map<char, string> hash1;
        unordered_map<string, char> hash2;
        while(i < len1 && j < len2) {
            int pos = str.find(' ', j);
            string s = str.substr(j, pos-j);
            if (hash1.count(pattern[i]) && hash1[pattern[i]] != s) return false;
            if (hash2.count(s) && hash2[s] != pattern[i]) return false;
            hash1[pattern[i]] = s;
            hash2[s] = pattern[i];
            i++, j = pos + 1;
        }
        return i == len1 && j == len2;
    }
};