LeetCode: Word Break

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, given
s = "leetcode",
dict = ["leet", "code"].

Return true because "leetcode" can be segmented as "leet code".

   bool wordBreak(string s, unordered_set<string> &dict) {  
     int l = s.length();  
     vector< vector<int> > m (l, vector<int>(l,0));  
     for (int i = 0; i <l; i++)  
     {  
       for (int j = i; j < l; j++)  
       {  
         if (dict.find(s.substr(i,j-i+1)) != dict.end())m[i][j] = 1;  
       }  
     }  
     for (int k = 2; k<=l ; k++)  
     {  
       for(int i = 0; i+k-1 < l ; i++)  
       {  
         int j = i+k-1;  
         for (int p = i; p <j; p++)  
         {  
           if(m[i][p] && m[p+1][j]){m[i][j] = true; break;}  
         }  
       }  
     }  
     return m[0][l-1];  
   }