Longest Ideal Subsequence
You are given a string s consisting of lowercase letters and an integer k. We call a string t ideal if the following conditions are satisfied:
tis a subsequence of the strings.- The absolute difference in the alphabet order of every two adjacent letters in
tis less than or equal tok.
Return the length of the longest ideal string.
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.
Note that the alphabet order is not cyclic. For example, the absolute difference in the alphabet order of 'a' and 'z' is 25, not 1.
Example 1
Input
s = "acfgbd", k = 2Output
4The longest ideal string is "acbd", whose length is 4; "acfgbd" is not ideal because 'c' and 'f' differ by 3 in alphabet order.
Example 2
Input
s = "abcd", k = 3Output
4The longest ideal string is "abcd", whose length is 4.
Constraints
- 1 <= s.length <= 10^5
- 0 <= k <= 25
- s consists of lowercase English letters.