Append Characters to String to Make Subsequence
You are given two strings s and t consisting of only lowercase English letters.
Return the minimum number of characters that need to be appended to the end of s so that t becomes a subsequence of s.
A subsequence is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters.
Example 1:
Input: s = "coaching", t = "coding"
Output: 4Explanation: Append the characters "ding" to the end of s so that s = "coachingding".
Now, t is a subsequence of s (coachingding).
It can be shown that appending any 3 characters to the end of s will never make t a subsequence.
Example 2:
Input: s = "abcde", t = "a"
Output: 0Explanation: t is already a subsequence of s ("a" from s).
Example 3:
Input: s = "z", t = "abcde"
Output: 5Explanation: Append the characters "abcde" to the end of s so that s = "zabcde".
Now, t is a subsequence of s (zabcde).
It can be shown that appending any 4 characters to the end of s will never make t a subsequence.
Constraints:
1 <= s.length, t.length <= 100,000sandtconsist of lowercase English letters.