Leetcode 3029. Minimum Time to Revert Word to Initial State I

Given a string and integer k, you repeatedly remove the first k characters and append any k characters to the end; compute the minimum positive number of such operations needed to restore the string to its original configuration. The core challenge is analyzing the position permutation induced by the remove-and-append step to find the smallest number of iterations (cycle/period) that allows the original arrangement to be reconstructed.