- Difficulty: Hard
- Tags: LeetCode, Hard, String, Binary Search, Suffix Array, Sliding Window, Hash Function, Rolling Hash, leetcode-1044, O(nlogn), O(n), Rabin-Karp Algorithm, Suffix Tree, Ukkonen's Algorithm
Problem
Given a string s, consider all duplicated substrings: (contiguous) substrings of s that occur 2 or more times. The occurrences may overlap.
Return any duplicated substring that has the longest possible length. If s does not have a duplicated substring, the answer is "".
Example 1:
Input: s = "banana" Output: "ana"
Example 2:
Input: s = "abcd" Output: ""
Constraints:
2 <= s.length <= 3 * 104sconsists of lowercase English letters.