asdfasdf

check_sequences.java

public interface Differ<T> {
   public Object diff(T t1, T t2);
}

Differ<SomeType> differ = getInstance();
SomeType a[];
int N = a.length();

Object delta;
if (N < 2){
    throw new Error("too small");
} else {
    delta = differ.diff(a[1], a[0]);
}

for (int i=1; i < N - 1; i++){
   if (delta.equals(differ.diff(a[i+1], a[i]))
        throw new Error("wrong");
}