Given a string s, partition s such that every substring of the partition is a palindrome. Return all possible palindrome partitioning of s. A palindrome string is a string that reads the same backward as forward. Example 1: Input: s = "aab" Output: [["a","a","b"],["aa","b"]] Example 2: Input: s = "a" Output: [["a"]] Constraints: 1 <= s.length <= 16 s contains only lowercase English letters.