LeetCode in Kotlin
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 (“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: 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 (“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 <= 105sandtconsist only of lowercase English letters.
Solution
class Solution {
fun appendCharacters(s: String, t: String): Int {
val lengthOfT = t.length
var indexOfT = 0
var indexOfS = 0
var position: Int
if (s.contains(t)) {
return 0
}
while (indexOfT < lengthOfT) {
position = s.indexOf(t[indexOfT], indexOfS)
if (position < 0) {
return lengthOfT - indexOfT
}
indexOfS = position
indexOfT++
indexOfS++
}
return lengthOfT - indexOfT
}
}