139. Word Break

class Solution {
public:
    bool wordBreak(string s, vector<string>& wordDict) {
        set<string> words;
        for(int i=0;i<wordDict.size();i++)
            words.insert(wordDict[i]);

        vector<bool> dp(s.size(),0);
        for(int i=s.size()-1;i>=0;i--)
        {
            string temp;
            temp=s.substr(i);
            if(words.count(temp)!=0)
                dp[i]=1;
            else
            {
                for(int j=i+1;j<s.size();j++)
                {
                    if(dp[j]==1)
                    {
                        temp=s.substr(i,j-i);
                        if(words.count(temp)!=0)
                            dp[i]=1;
                    }
                }
            }
        }
        return dp[0];
    }
};