3137. Minimum Number of Operations to Make Word K-Periodic

You are given a string word of size n, and an integer k such that k divides n.

In one operation, you can pick any two indices i and j, that are divisible by k, then replace the 

substring

of lengthkstarting atiwith the substring of lengthkstarting atj. That is, replace the substringword[i..i + k - 1]with the substringword[j..j + k - 1].Return the minimum number of operations required to make word k-periodic.

We say that word is k-periodic if there is some string s of length k such that word can be obtained by concatenating s an arbitrary number of times. For example, if word == “ababab”, then word is 2-periodic for s = "ab".

Example 1:

Input: word = "leetcodeleet", k = 4

Output: 1

Explanation:

We can obtain a 4-periodic string by picking i = 4 and j = 0. After this operation, word becomes equal to "leetleetleet".

Example 2:

Input: word = "leetcoleet", k = 2

Output: 3

Constraints:

• 1 <= n == word.length <= 105
• 1 <= k <= word.length
• k divides word.length.
• word consists only of lowercase English letters.