131. Palindrome Partitioning

https://leetcode.com/problems/palindrome-partitioning/

1. Use backtracking:

//60 ms    15.8 MB
class Solution {
public:
    vector<vector<string>> partition(string s) {
        vector<string> path;
        vector<vector<string>> result;
        backtrack(s, path, result, 0);
        return result;
    }
private:
    bool isPallindrome(string s){
        int l = 0, r = s.length()-1;
        while(l < r){
            if(s[l] != s[r]){
                return false;
            }
            l++;
            r--;
        }
        return true;
    }
    void backtrack(string s, vector<string>& path, vector<vector<string>>& result, int pos){
        int n = s.size();
        if(pos == n){
            result.push_back(path);
            return;
        }
        for(int i=1; i<= n - pos; i++){
            if(isPallindrome(s.substr(pos, i))){
                path.push_back(s.substr(pos, i));
                backtrack(s, path, result, pos+i);
                path.pop_back();
            }
        }
    }
};