LeetCode in Kotlin

409. Longest Palindrome

Easy

Given a string s which consists of lowercase or uppercase letters, return the length of the longest palindrome that can be built with those letters.

Letters are case sensitive, for example, "Aa" is not considered a palindrome here.

Example 1:

Input: s = “abccccdd”

Output: 7

Explanation: One longest palindrome that can be built is “dccaccd”, whose length is 7.

Example 2:

Input: s = “a”

Output: 1

Explanation: The longest palindrome that can be built is “a”, whose length is 1.

Constraints:

Solution

import java.util.BitSet

class Solution {
    fun longestPalindrome(s: String): Int {
        val set = BitSet(60)
        for (c in s.toCharArray()) {
            set.flip(c.code - 'A'.code)
        }
        return if (set.isEmpty()) {
            s.length
        } else {
            s.length - set.cardinality() + 1
        }
    }
}