131. Palindrome Partitioning

Given a strings, partitionssuch that every substring of the partition is a palindrome.

Return all possible palindrome partitioning ofs.

For example, givens="aab",Return

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

思路：用经典traceback

public class Solution {
    public List<List<String>> partition(String s) {
        List<List<String>> res = new ArrayList<List<String>>();
        if (s==null||s.length()==0) return res;
        List<String> temp = new ArrayList<String>();
        traceBack(res, temp, s, 0);
        return res;
    }

    public void traceBack(List<List<String>> res, List<String> temp, String s, int startInd){
        if (startInd == s.length()){
            res.add(new ArrayList<String>(temp));
            return;
        }

        for (int i=startInd;i<s.length();i++){
            String subString = s.substring(startInd,i+1);
            if (isPalindrome(subString)){
                temp.add(subString);
                traceBack(res,temp,s,i+1);
                temp.remove(temp.size()-1);
            }
        }
    }

    public boolean isPalindrome(String s){
        int left = 0;
        int right = s.length()-1;
        while(left<right){
            if(s.charAt(left)!=s.charAt(right)){
                return false;
            } 
            left++;
            right--;
        }
        return true;
    }
}