import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.Test;
import java.util.List;
import java.util.Arrays;
import java.util.ArrayList;
public class Main {
    //Program start
    
    //Program end

    @Test
public void test1() {
    assertEquals(3, longestAlternatingSubarray(new ArrayList<>(Arrays.asList(3,2,5,4)), 5));
}
@Test
public void test2() {
    assertEquals(1, longestAlternatingSubarray(new ArrayList<>(Arrays.asList(1,2)), 2));
}
@Test
public void test3() {
    assertEquals(3, longestAlternatingSubarray(new ArrayList<>(Arrays.asList(2,3,4,5)), 4));
}

}