统计各个字符串出现次数进行判断

#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;
#define int long long
const int mod=1e+7;
signed main() {
    iostream::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    string s;cin>>s;
    vector<int> a(128);
    for(int i=0;i<s.length();i++){
        a[s[i]]++;
    }
    int ans=0,num=0;
    for(int i=0;i<128;i++){
        ans+=a[i]/2*2;
        if(a[i]%2==1)num++;
    }
    if(num>0){
        ans++;
    }
    cout<<ans<<endl;
    return 0;
 }

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        int[] arr = new int[200];
        for (int i = 0; i < str.length(); i++) {
            arr[str.charAt(i) - 'A']++;
        }
        int ans = 0;
        int flag = 0;
        for (int i = 0; i < 200; i++) {
            ans += arr[i] / 2 * 2;
            arr[i] %= 2;
            if(arr[i] == 1) flag = 1;
        }
        if(flag == 1) ans++;
        System.out.println(ans);
    }
}