38. Palindrome Partitioning

题目

Given a string s, partition s such that every substring of the partition is a palindrome.

Return all possible palindrome partitioning of s.

For example, given s = "aab",
Return

[
["aa","b"],
["a","a","b"]
]

解题之法

class Solution {
public:
    vector<vector<string>> partition(string s) {
        vector<vector<string> > ret;
        if(s.empty()) return ret;
        
        vector<string> path;
        dfs(0, s, path, ret);
        
        return ret;
    }
    
    void dfs(int index, string& s, vector<string>& path, vector<vector<string> >& ret) {
        if(index == s.size()) {
            ret.push_back(path);
            return;
        }
        for(int i = index; i < s.size(); ++i) {
            if(isPalindrome(s, index, i)) {
                path.push_back(s.substr(index, i - index + 1));
                dfs(i+1, s, path, ret);
                path.pop_back();
            }
        }
    }
    
    bool isPalindrome(const string& s, int start, int end) {
        while(start <= end) {
            if(s[start++] != s[end--])
                return false;
        }
        return true;
    }
};