3503 - Longest Palindrome After Substring Concatenation I.

Medium

You are given two strings, s and t.

You can create a new string by selecting a substring from s (possibly empty) and a substring from t (possibly empty), then concatenating them in order.

Return the length of the longest palindrome that can be formed this way.

Example 1:

Input: s = "a", t = "a"

Output: 2

Explanation:

Concatenating "a" from s and "a" from t results in "aa", which is a palindrome of length 2.

Example 2:

Input: s = "abc", t = "def"

Output: 1

Explanation:

Since all characters are different, the longest palindrome is any single character, so the answer is 1.

Example 3:

Input: s = "b", t = "aaaa"

Output: 4

Explanation:

Selecting "aaaa" from t is the longest palindrome, so the answer is 4.

Example 4:

Input: s = "abcde", t = "ecdba"

Output: 5

Explanation:

Concatenating "abc" from s and "ba" from t results in "abcba", which is a palindrome of length 5.

Constraints:

• 1 <= s.length, t.length <= 30

• s and t consist of lowercase English letters.