Longest Palindrome

class Solution {
public:
    int longestPalindrome(string s) {
        int cnt[128] = {0};
        for (char c : s) ++cnt[(unsigned char)c];
        int total = 0;
        bool hasOdd = false;
        for (int i = 0; i < 128; ++i) {
            total += cnt[i] & ~1;       // drop the low bit
            if (cnt[i] & 1) hasOdd = true;
        }
        return total + (hasOdd ? 1 : 0);
    }
};

func longestPalindrome(s string) int {
    var cnt [128]int
    for i := 0; i < len(s); i++ {
        cnt[s[i]]++
    }
    total := 0
    hasOdd := false
    for i := 0; i < 128; i++ {
        total += cnt[i] &^ 1
        if cnt[i]&1 == 1 {
            hasOdd = true
        }
    }
    if hasOdd {
        total++
    }
    return total
}

from collections import Counter

class Solution:
    def longestPalindrome(self, s: str) -> int:
        cnt = Counter(s)
        total = 0
        has_odd = False
        for c in cnt.values():
            total += c & ~1
            if c & 1:
                has_odd = True
        return total + (1 if has_odd else 0)

function longestPalindrome(s) {
    const cnt = new Map();
    for (const c of s) cnt.set(c, (cnt.get(c) ?? 0) + 1);
    let total = 0;
    let hasOdd = false;
    for (const c of cnt.values()) {
        total += c & ~1;
        if (c & 1) hasOdd = true;
    }
    return total + (hasOdd ? 1 : 0);
}

class Solution {
    public int longestPalindrome(String s) {
        int[] cnt = new int[128];
        for (int i = 0; i < s.length(); i++) cnt[s.charAt(i)]++;
        int total = 0;
        boolean hasOdd = false;
        for (int i = 0; i < 128; i++) {
            total += cnt[i] & ~1;
            if ((cnt[i] & 1) == 1) hasOdd = true;
        }
        return total + (hasOdd ? 1 : 0);
    }
}

function longestPalindrome(s: string): number {
    const cnt = new Map<string, number>();
    for (const c of s) cnt.set(c, (cnt.get(c) ?? 0) + 1);
    let total = 0;
    let hasOdd = false;
    for (const c of cnt.values()) {
        total += c & ~1;
        if (c & 1) hasOdd = true;
    }
    return total + (hasOdd ? 1 : 0);
}