[Leetcode][JAVA] Palindrome Partitioning

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"]
  ]


回溯算法，需要注意的就是在得到子串时判断是否为回文字符串（需要自己写函数），如果是才继续展开下一层。
代码：

public List<List<String>> partition(String s) {
        List<List<String>> re = new ArrayList<List<String>>();
        if(s==null || s.length()==0)
            return re;
        List<String> path = new ArrayList<String>();
        collect(re, path, s, 0);
        return re;
    }
    public void collect(List<List<String>> re, List<String> path, String s, int start)
    {
        for(int i=start+1;i<=s.length();i++)
        {
            String temp = s.substring(start,i);
            if(!isP(temp))
                continue;
            path.add(temp);
            if(i==s.length())
                re.add(new ArrayList<String>(path));
            else
                collect(re, path, s, i);
            path.remove(path.size()-1);
        }
    }
    public boolean isP(String x)
    {
        int p = 0;
        int q = x.length()-1;
        while(p<q)
        {
            if(x.charAt(p)!=x.charAt(q))
                return false;
            p++;
            q--;
        }
        return true;
    }