Problem:
Score : 100 points

Problem Statement

You are given a 4-character string S consisting of uppercase English letters.
Determine if S consists of exactly two kinds of characters which both appear twice in S.

Constraints

The length of S is 4.

S consists of uppercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If S consists of exactly two kinds of characters which both appear twice in S, print Yes; otherwise, print No.

Sample Input 1

ASSA

Sample Output 1

Yes

S consists of A and S which both appear twice in S.

Sample Input 2

STOP

Sample Output 2

No

Sample Input 3

FFEE

Sample Output 3

Yes

Sample Input 4

FREE

Sample Output 4

No

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)


import java.util.Scanner;
import java.util.Arrays;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) {
        //コード
        Scanner scanner = new Scanner(System.in);
        String x = scanner.next();
        String[] ar = x.split("");
        int count = 0;
        int no_count = 0;

        for(int i = 0; i< ar.length; i++) {
            String s = ar[i];
            for(int j = 0; j < ar.length; j++) {
                if (s.equals(ar[j])) count++;
            }
            if(count >= 2) break;
            count = 0;
        }

        for(int i = 0; i< 2; i++) {
            if(ar[i].equals(ar[0])) no_count++;
            if(ar[i].equals(ar[1])) no_count++;
            if(ar[i].equals(ar[2])) no_count++;
            if(ar[i].equals(ar[3])) no_count++;
        }

        if(count >= 2 && no_count == 4) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

    }
}