leetcode -- Palindrome Partitioning

 1 vector<vector<string>> Solution::partition(string s){
 2     const int len = s.length();
 3     bool dp[len][len];
 4     fill_n(&dp[0][0], len*len, false);
 5     for (int i = len-1; i >=0; i --){
 6         for (int j = i; j < len; j++){
 7             dp[i][j] = s[i]==s[j]&&(j-i<2||dp[i+1][j-1]);
 8         }
 9     }
10     vector<vector<string>> ans[len];
11     for (int i = len-1; i>=0; i--){
12         for (int j = i; j < len; j++){
13             if (dp[i][j] == 1){
14                 const string tmp = s.substr(i, j-i+1);
15                 if (j + 1 >= len){
16                     ans[i].push_back(vector<string> {tmp});
17                 }
18                 else{
19                     for (auto k : ans[j + 1]){
20                         k.insert(k.begin(), tmp);
21                         ans[i].push_back(k);
22                     }
23                 }
24             }
25         }
26     }
27     return ans[0];
28 }