#![allow(dead_code, unused, unused_variables)]

fn main() {}

struct Solution;

impl Solution {
    pub fn longest_palindrome(s: String) -> i32 {
        let mut hash = std::collections::HashMap::new();
        s.as_bytes().into_iter().for_each(|x| {
            hash.entry(x).and_modify(|v| *v += 1).or_insert(1);
        });

        let mut odd = false; // 是否有单数，如果有单数的话，则最后的结果+1

        let mut r = 0;

        hash.into_iter().for_each(|(_, v)| {
            if v % 2 == 0 {
                r += v;
            } else {
                odd = true;
                r += v - 1;
            }
        });

        if odd {
            r + 1
        } else {
            r
        }
    }
}