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.

Example:

Input: "aab"
Output:
[
  ["aa","b"],
  ["a","a","b"]
]

class Solution {
    public List<List<String>> partition(String s) {
        List<List<String>> ans = new ArrayList<>();
        backTrack(s, ans, new ArrayList<String>(), 0);
        return ans;
    }

    public void backTrack(String s, List<List<String>> ans, ArrayList<String> temp, int start) {
        if (start == s.length()) {
            ans.add(new ArrayList<>(temp));
            return;
        }
        for (int i = start; i < s.length(); i++) {
            if (isPalindrome(s, start, i)) {
                temp.add(s.substring(start, i + 1));
                backTrack(s, ans, temp, i + 1);
                temp.remove(temp.size() - 1);
            }
        }
    }

    public boolean isPalindrome(String str, int start, int end) {
        while (start <= end) {
            if (str.charAt(start) != str.charAt(end))
                return false;
            start++;
            end--;
        }
        return true;
    }
}