LCS

import java.util.ArrayList;
import java.util.PriorityQueue;

/**
 *
 * @author juliuuus
 */
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        IO io = new IO();

        String sana1 = io.next();
        String sana2 = io.next();

        int alaraja = 0;
        int koko = 0;

        for (int i = 0; i < sana1.length(); i++) {
            for (int j = alaraja; j < sana2.length(); j++) {

                if (sana1.charAt(i) == sana2.charAt(j)) {
                    koko++;
                    alaraja = j+1;
                    break;
                }
            }
            if (alaraja >= sana2.length()) {
                break;
            }
        }
        io.println(koko);
        io.close();
    }

}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: WRONG ANSWER

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: WRONG ANSWER

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: WRONG ANSWER

Test 31

Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

Test 33

Verdict: WRONG ANSWER

Test 34

Verdict: WRONG ANSWER

Test 35

Verdict: WRONG ANSWER

Test 36

Verdict: WRONG ANSWER

Test 37

Verdict: WRONG ANSWER

Test 38

Verdict: WRONG ANSWER

Test 39

Verdict: WRONG ANSWER

Test 40

Verdict: ACCEPTED

Test 41

Verdict: WRONG ANSWER

Test 42

Verdict: WRONG ANSWER

Test 43

Verdict: ACCEPTED

Test 44

Verdict: ACCEPTED

Test 45

Verdict: ACCEPTED

Test 46

Verdict: ACCEPTED

Test 47

Verdict: ACCEPTED

Test 48

Verdict: ACCEPTED

Test 49

Verdict: WRONG ANSWER

Test 50

Verdict: ACCEPTED