Language: C++

import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        char[] S = sc.next().toCharArray();
        int len = S.length;
        int[] cnt = new int[26];
        for(char c : S) {
            cnt[c - 'a']++;
        }

        int odd = 0, even = 0;
        for(int n : cnt) {
            if(n % 2 == 0) even++;
            else odd++;
        }
        if(len % 2 == 0 && odd == 0) {
            long k = fact(len / 2);
            for(int n : cnt) {
                k /= (fact(n / 2));
            }
            System.out.println(k);

        }
        else if(len % 2 == 1 && odd == 1) {
            long k = fact(len / 2);
            for(int n : cnt) {
                k /= (fact(n / 2));
            }
            System.out.println(k);
        }
        else {
            System.out.println(0);
        }
    }

    static long fact(int n) {
        return n < 2 ? 1 : n * fact(n - 1);
    }
}

Compiler output:
a.cc:1:1: error: 'import' does not name a type
    1 | import java.util.*;
      | ^~~~~~
a.cc:1:1: note: C++20 'import' only available with '-fmodules-ts'
a.cc:4:11: error: expected ':' before 'static'
    4 |     public static void main(String[] args) {
      |           ^~~~~~~
      |           :
a.cc:4:29: error: 'String' has not been declared
    4 |     public static void main(String[] args) {
      |                             ^~~~~~
a.cc:4:38: error: expected ',' or '...' before 'args'
    4 |     public static void main(String[] args) {
      |                                      ^~~~
a.cc:41:2: error: expected ';' after class definition
   41 | }
      |  ^
      |  ;
a.cc: In static member function 'static void Main::main(int*)':
a.cc:5:9: error: 'Scanner' was not declared in this scope
    5 |         Scanner sc = new Scanner(System.in);
      |         ^~~~~~~
a.cc:6:13: error: structured binding declaration cannot have type 'char'
    6 |         char[] S = sc.next().toCharArray();
      |             ^~
a.cc:6:13: note: type must be cv-qualified 'auto' or reference to cv-qualified 'auto'
a.cc:6:13: error: empty structured binding declaration
a.cc:6:16: error: expected initializer before 'S'
    6 |         char[] S = sc.next().toCharArray();
      |                ^
a.cc:7:19: error: 'S' was not declared in this scope
    7 |         int len = S.length;
      |                   ^
a.cc:8:12: error: structured binding declaration cannot have type 'int'
    8 |         int[] cnt = new int[26];
      |            ^~
a.cc:8:12: note: type must be cv-qualified 'auto' or reference to cv-qualified 'auto'
a.cc:8:12: error: empty structured binding declaration
a.cc:8:15: error: expected initializer before 'cnt'
    8 |         int[] cnt = new int[26];
      |               ^~~
a.cc:10:13: error: 'cnt' was not declared in this scope; did you mean 'int'?
   10 |             cnt[c - 'a']++;
      |             ^~~
      |             int
a.cc:14:21: error: 'cnt' was not declared in this scope; did you mean 'int'?
   14 |         for(int n : cnt) {
      |                     ^~~
      |                     int
a.cc:20:25: error: 'cnt' was not declared in this scope; did you mean 'int'?
   20 |             for(int n : cnt) {
      |                         ^~~
      |                         int
a.cc:23:13: error: 'System' was not declared in this scope
   23 |             System.out.println(k);
      |             ^~~~~~
a.cc:28:25: error: 'cnt' was not declared in this scope; did you mean 'int'?
   28 |             for(int n : cnt) {
      |                         ^~~
      |                         int
a.cc:31:13: error: 'System' was not declared in this scope
   31 |             System.out.println(k);
      |             ^~~~~~
a.cc:34:13: error: 'System' was not declared in this scope
   34 |             System.out.println(0);
      |             ^~~~~~