Palindrome Partitioning

注意add arraylist<E> 到 ArrayList<ArrayList<E>>的时候传递引用和传值得区别！！！

public class Solution {
    public ArrayList<ArrayList<String>> partition(String s) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        ArrayList<ArrayList<String>> result = new ArrayList<ArrayList<String>>();
        if(s == null || s.length() == 0)
            return result;
        ArrayList<String> stringList = new ArrayList<String>();
        PaPartition(s, 0, s.length(), stringList, result);
        return result;
    }
    private boolean isPalindrome(String s, int start, int end)
    {
        while(start < end - 1)
        {
            if(s.charAt(start) != s.charAt(end - 1))
                return false;
            start ++;
            end --;
        }
        return true;
    }
    private void PaPartition(String s, int start, int end, ArrayList<String> stringList, ArrayList<ArrayList<String>> result)
    {
        if(start >= end)
        {
            ArrayList<String> tmp = new ArrayList<String>();
　　　　　　　tmp.addAll(stringList);
            result.add(tmp);
            return;
        }
        for(int i = start + 1; i <= end; i++)
        {
            if(isPalindrome(s, start, i))
            {
                stringList.add(s.substring(start, i));
                PaPartition(s, i, end, stringList, result);
                stringList.remove(stringList.size() - 1);
            }
        }
    }
}