1163\. Last Substring in Lexicographical Order

Hard

Given a string `s`, return _the last substring of_ `s` _in lexicographical order_.

**Example 1:**

**Input:** s = "abab"

**Output:** "bab"

**Explanation:** The substrings are ["a", "ab", "aba", "abab", "b", "ba", "bab"]. The lexicographically maximum substring is "bab".

**Example 2:**

**Input:** s = "leetcode"

**Output:** "tcode"

**Constraints:**

*   <code>1 <= s.length <= 4 * 10<sup>5</sup></code>
*   `s` contains only lowercase English letters.