LeetCode-in-Java
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
public class Solution {
public int appendCharacters(String s, String t) {
int lengthOfT = t.length();
int indexOfT = 0;
int indexOfS = 0;
int position;
if (s.contains(t)) {
return 0;
}
while (indexOfT < lengthOfT) {
position = s.indexOf(t.charAt(indexOfT), indexOfS);
if (position < 0) {
return lengthOfT - indexOfT;
}
indexOfS = position;
indexOfT++;
indexOfS++;
}
return lengthOfT - (indexOfT);
}
}