LeetCode in Kotlin
3628. Maximum Number of Subsequences After One Inserting
Medium
You are given a string s consisting of uppercase English letters.
You are allowed to insert at most one uppercase English letter at any position (including the beginning or end) of the string.
Return the maximum number of "LCT" subsequences that can be formed in the resulting string after at most one insertion.
Example 1:
Input: s = “LMCT”
Output: 2
Explanation:
We can insert a "L" at the beginning of the string s to make "LLMCT", which has 2 subsequences, at indices [0, 3, 4] and [1, 3, 4].
Example 2:
Input: s = “LCCT”
Output: 4
Explanation:
We can insert a "L" at the beginning of the string s to make "LLCCT", which has 4 subsequences, at indices [0, 2, 4], [0, 3, 4], [1, 2, 4] and [1, 3, 4].
Example 3:
Input: s = “L”
Output: 0
Explanation:
Since it is not possible to obtain the subsequence "LCT" by inserting a single letter, the result is 0.
Constraints:
1 <= s.length <= 105sconsists of uppercase English letters.
Solution
class Solution {
fun numOfSubsequences(s: String): Long {
var tc: Long = 0
val chs = s.toCharArray()
for (c in chs) {
tc += (if (c == 'T') 1 else 0).toLong()
}
var ls: Long = 0
var cs: Long = 0
var lcf: Long = 0
var ctf: Long = 0
var lct: Long = 0
var ocg: Long = 0
var tp: Long = 0
for (curr in chs) {
val rt = tc - tp
val cg = ls * rt
ocg = if (cg > ocg) cg else ocg
if (curr == 'L') {
ls++
} else {
if (curr == 'C') {
cs++
lcf += ls
} else {
if (curr == 'T') {
lct += lcf
ctf += cs
tp++
}
}
}
}
val fcg = ls * (tc - tp)
ocg = if (fcg > ocg) fcg else ocg
var maxi: Long = 0
val bo = longArrayOf(lcf, ctf, ocg)
for (op in bo) {
maxi = if (op > maxi) op else maxi
}
return lct + maxi
}
}