Doubly linked list
How to seek immediate predecessor the list p nodes, how to time their performance?
From the current loop through node p immediate predecessor node is determined, the time complexity is O (n).
By p-> next successor node can directly access the node p, the time complexity is O (1).
How to quickly get p node precursor nodes?
Add a pointer points to the predecessor node by node domain.
Doubly linked list: each node in the linked list in a single setting a pointer field, pointing to its precursor nodes.
data: data storage elements; next: the storage node successor node address; prior: predecessor node storing the node address.
Doubly linked list node structure is defined:
typedef strcut DuLNode{
ElemType data; //数据域
struct PuLNode *prior; //指向前驱结点的指针
struct PuLNode *next; //指向后继结点的指针
}DuLNode, *DuLinkList;
Doubly linked list insertion:
S predecessor node pointer pointing to the node p, p original successor node pointers redirected s precursor pointer field, a pointer directed to the subsequent original domain assigned to the successor of s.
s-> prior = p; s-> next-> prior = s; // s-> next original is a [i] node, prior pointer field a [i] of the node junction point s
s-> next = p-> next; // pointer field reassignment
Doubly linked list insertion: the insertion position of the i-th node e
bool ListInsert_DuL(DuLinkList &L , int i, ElemType e){
if(!(p = GetElem_DuL(L,i)))) //查找第i个元素的结点吗，操作和单链表一样
return false;
s = (List)malloc(sizeof(DuLNode)); //分配新节点s内存空间
s->data = e;
s->next = p->next;
p->next->prior = s;
p->next = s;
return true;
}Deletion of the i-node:
Demo:
bool ListDelete_Dul(DuLinkList &L, int i, ElemType e){
p->prior->next = p->next; //第一步
p->next->prior = p->prior; //第二步
free(p); //释放p结点的内存空间
return true;
}Although higher operational efficiency of the doubly linked list, each node requires a pointer field occupies an extra space complexity doubled.
