Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.For example, givens = "leetcode",dict = ["leet", "code"].Return true because "leetcode" can be segmented as "leet code".

class Solution {public:    bool wordBreak(string s, unordered_set<string> &dict) {        std::vector<bool> dp(s.size() + 1, false);          dp[0] = true;        for (int i = 1; i <= s.size(); ++i) {            for (int j = i - 1; j >= 0; --j) {                std::string str = s.substr(j, i - j);                if (dp.at(j) == true && dict.find(str) != dict.end()) {                    dp.at(i) = true;                }            }        }        return dp.at(s.size());    }};

Given a string s and a dictionary of words dict, add spaces in s to construct a sentence where each word is a valid dictionary word.Return all such possible sentences.For example, givens = "catsanddog",dict = ["cat", "cats", "and", "sand", "dog"].A solution is ["cats and dog", "cat sand dog"].