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class Solution {
public:
    bool **map;
    set<int> wordlens;
    vector<string> result;
    vector<string> wordBreak(string s, unordered_set<string> &dict) {
        wordlens.clear();
        unordered_set<string>::iterator it;
        for(it = dict.begin(); it != dict.end(); it++) {
            string itstr = *it;
            wordlens.insert(itstr.length());
        }
        result.clear();
        map = new bool*[s.length()];
        for(int i = 0; i < s.length(); i++) {
            map[i] = new bool[s.length()];
            for(int j = 0; j < s.length(); j++) {
                map[i][j] = false;
            }
        }
        for(int start = 0; start < s.length(); start++) {
            for(int len = 1; len <= s.length() - start; len++) {
                string tmp = s.substr(start, len);
                if(dict.find(tmp) != dict.end()) {
                    map[start][start + len - 1] = true;
                }
            }
        }
        for(int i = 0; i < s.length(); i++) {
            for(int j = 0; j <= i; j++) {
                for(int k = j; k < i; k++) {
                    if(map[j][k] && map[k + 1][i]) map[j][i] = true;
                }
            }
        }
        // for(int i = 0; i < s.length(); i++) {
        //   for(int j = 0; j < s.length(); j++) {
        //      cout << map[i][j] << ' ';
        //   }
        //   cout << endl;
        // }
        if(map[0][s.length() - 1] == false) return result;
        string item = "";
        findSen(s, 0, dict, item);
        return result;
    }
private:
    void findSen(string &s, int start, unordered_set<string> &dict, string &item) {
        if(start >= s.length()) {
            result.push_back(item);
            return;
        }
        set<int>::iterator it;
        for(it = wordlens.begin(); it != wordlens.end(); it++) {
            int len = *it;
            if(start + len > s.length()) return;
            string tmp = string(s, start, len);
            if(dict.find(tmp) != dict.end()) {
                string itembp = item;
                if(start != 0) item += " ";
                item += tmp;
                findSen(s, start + len, dict, item);
                item = itembp;
            }
        }
    }
};