You are given a string word.
Return the maximum number of non-intersecting substrings of word that are at least four characters long and start and end with the same letter.
A substring is a contiguous non-empty sequence of characters within a string.
Example 1:
Input: word = "abcdeafdef"
Output: 2
Explanation:
The two substrings are "abcdea" and "fdef".
Example 2:
Input: word = "bcdaaaab"
Output: 1
Explanation:
The only substring is "aaaa". Note that we cannot also choose "bcdaaaab" since it intersects with the other substring.
Constraints:
1 <= word.length <= 2 * 105word consists only of lowercase English letters.