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

    //Program end

    @Test
public void test1() {
    assertEquals(Arrays.asList(1,4), zigzagTraversal(Arrays.asList(Arrays.asList(1,2),Arrays.asList(3,4))));
}
@Test
public void test2() {
    assertEquals(Arrays.asList(2,1,2), zigzagTraversal(Arrays.asList(Arrays.asList(2,1),Arrays.asList(2,1),Arrays.asList(2,1))));
}
@Test
public void test3() {
    assertEquals(Arrays.asList(1,3,5,7,9), zigzagTraversal(Arrays.asList(Arrays.asList(1,2,3),Arrays.asList(4,5,6),Arrays.asList(7,8,9))));
}

}