DEV Community

Cover image for 2486. Append Characters to String to Make Subsequence
MD ARIFUL HAQUE
MD ARIFUL HAQUE

Posted on • Edited on

2486. Append Characters to String to Make Subsequence

2486. Append Characters to String to Make Subsequence

Medium

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: 4
  • Explanation: Append the characters "ding" to the end of s so that s = "coachingding".\ Now, t is a subsequence of s ("coaching*ding*").\ 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: 0
  • Explanation: t is already a subsequence of s ("abcde").

Example 3:

  • Input: s = "z", t = "abcde"
  • Output: 5
  • Explanation: Append the characters "abcde" to the end of s so that s = "zabcde".\ Now, t is a subsequence of s ("z*abcde*").\ 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 <= 105
  • s and t consist only of lowercase English letters.

Solution:

class Solution {

    /**
     * @param String $s
     * @param String $t
     * @return Integer
     */
    function appendCharacters($s, $t) {
        $i = 0;

        foreach(str_split($s) as $c) {
            if ($c == $t[$i]) {
                if (++$i == strlen($t)) {
                    return 0;
                }
            }
        }

        return strlen($t) - $i;
    }
}
Enter fullscreen mode Exit fullscreen mode

Contact Links

If you found this series helpful, please consider giving the repository a star on GitHub or sharing the post on your favorite social networks 😍. Your support would mean a lot to me!

If you want more helpful content like this, feel free to follow me:

Speedy emails, satisfied customers

Postmark Image

Are delayed transactional emails costing you user satisfaction? Postmark delivers your emails almost instantly, keeping your customers happy and connected.

Sign up

Top comments (0)

Billboard image

Create up to 10 Postgres Databases on Neon's free plan.

If you're starting a new project, Neon has got your databases covered. No credit cards. No trials. No getting in your way.

Try Neon for Free →