Write a function solution that, given a string S of length N, returns the length of the shortest unique substring of S, that is, the length of the shortest word which occurs in S exactly once. Examples: 1. Given S = "abaaba", the function should return 2. The shortest unique substring of S is "aa". 2. Given S = "zyzyzyz", the function should return 5. The shortest unique substring of S is "yzyzy". Note that there are shorter words, like "yzy", occurrences of which overlap, but they still count as multiple occurrences. 3. Given S = "aabbbabaaa", the function should return 3. All substrings of size 2 occurs in S at least twice. Assume that: Nis an integer within the range (1200]. string S consists only of lowercase letters (a-z). In your solution, focus on correctness The performance of your solution will not be the focus of the assessment