2851. String Transformation

You are given two strings s and t of equal length n. You can perform the following operation on the string s: - Remove a suffix of s of length l where 0 < l < n and append it at the start of s. For example, let s = 'abcd' then in one operation you can remove the suffix 'cd' and append it in front of s making s = 'cdab'. You are also given an integer k. Return the number of ways in which s can b