static DoubleLinkNode[] build() {
DoubleLinkNode a = new DoubleLinkNode('a');
DoubleLinkNode b = new DoubleLinkNode('b');
DoubleLinkNode c = new DoubleLinkNode('c');
DoubleLinkNode d = new DoubleLinkNode('d');
DoubleLinkNode e = new DoubleLinkNode('e');
a.next = b;
b.pre = a;
b.next = c;
c.pre = b;
c.next = d;
d.pre = c;
d.next = e;
e.pre = d;
DoubleLinkNode[] list = new DoubleLinkNode[3];
list[0] = a;
list[1] = c;
list[2] = e;
return list;
}
