public interface Snapshot<T> {
  public void update(T v);
  public T[] scan();
}

public class SeqSnapshot<T> implements Snapshot<T> {
  T[] a_value;
  public SeqSnapshot(int capacity, T init) {
    a_value = (T[]) new Object[capacity];
    for (int i = 0; i < a_value.length; i++) {
      a_value[i] = init;
    }
  }
  public synchronized void update(T v) {
    a_value[ThreadID.get()] = v;
  }
  public synchronized T[] scan() {
    T[] result = (T[]) new Object[a_value.length];
    for (int i = 0; i < a_value.length; i++)
    result[i] = a_value[i];
    return result;
  }
}