Решение

class Solution {
    fun longestPalindrome(s: String): Int {
        val cnt = IntArray(128)
        var i = 0
        val n = s.length
        while (i < n) {
            cnt[s[i].code]++
            i++
        }
        var res = 0
        var hasOdd = false
        i = 0
        while (i < 128) {
            val c = cnt[i]
            res += c and -2
            if ((c and 1) == 1) hasOdd = true
            i++
        }
        return if (hasOdd) res + 1 else res
    }
}