2781 - Length of the Longest Valid Substring\.

Hard

You are given a string word and an array of strings forbidden.

A string is called valid if none of its substrings are present in forbidden.

Return the length of the longest valid substring of the string word.

A substring is a contiguous sequence of characters in a string, possibly empty.

Example 1:

Input: word = "cbaaaabc", forbidden = "aaa","cb"

Output: 4

Explanation:

There are 9 valid substrings in word: "c", "b", "a", "ba", "aa", "bc", "baa", "aab", "ab", "abc"and "aabc". The length of the longest valid substring is 4.

It can be shown that all other substrings contain either "aaa" or "cb" as a substring.

Example 2:

Input: word = "leetcode", forbidden = "de","le","e"

Output: 4

Explanation:

There are 11 valid substrings in word: "l", "t", "c", "o", "d", "tc", "co", "od", "tco", "cod", and "tcod". The length of the longest valid substring is 4.

It can be shown that all other substrings contain either "de", "le", or "e" as a substring.

Constraints:

• <code>1 <= word.length <= 10⁵</code>

• word consists only of lowercase English letters.

• <code>1 <= forbidden.length <= 10⁵</code>

• 1 <= forbidden[i].length <= 10

• forbidden[i] consists only of lowercase English letters.