3303 - Find the Occurrence of First Almost Equal Substring.

Hard

You are given two strings s and pattern.

A string x is called almost equal to y if you can change at most one character in x to make it identical to y.

Return the smallest starting index of a substring in s that is almost equal to pattern. If no such index exists, return -1.

A substring is a contiguous non-empty sequence of characters within a string.

Example 1:

Input: s = "abcdefg", pattern = "bcdffg"

Output: 1

Explanation:

The substring s[1..6] == "bcdefg" can be converted to "bcdffg" by changing s[4] to "f".

Example 2:

Input: s = "ababbababa", pattern = "bacaba"

Output: 4

Explanation:

The substring s[4..9] == "bababa" can be converted to "bacaba" by changing s[6] to "c".

Example 3:

Input: s = "abcd", pattern = "dba"

Output: \-1

Example 4:

Input: s = "dde", pattern = "d"

Output: 0

Constraints:

• <code>1 <= pattern.length < s.length <= 3 * 10⁵</code>

• s and pattern consist only of lowercase English letters.

Follow-up: Could you solve the problem if at most k consecutive characters can be changed?