[英]Insert element into a sorted Circular Double Linked List
我想将元素插入到已排序的循环双链表中,这是我尝试的操作:
void insertSorted(Node *&head,int x){
Node *temp = new Node();
temp->data = x;
temp->next = temp;
temp->prev = temp;
if(head == NULL){
head = temp;
return;
}
Node *p = head;
Node *q = NULL;
do{
q = p;
p=p->next;
}while(p != head && x>p->data);
if(q == NULL){
temp->next = head;
head->prev = temp;
head = temp;
}
else {
q->next = temp;
if(p!=NULL){
temp->next = p;
p->prev = temp;
}
temp->prev = q;
}
}
代码可以工作,但是问题是每次不排序时第一个元素都会出现问题,例如插入10 9 8 1 2,例如,输出将是10 1 2 8 9,应该是1 2 8 9 10
if(q == NULL)
永远不会按照您的代码发生。 因此,这里出现问题。
当第一个节点出现问题时,条件应为(q == head)
并更新head。 您的代码执行正确。
void sortedInsert(int data){
Nodo* ins = (Nodo*)malloc(sizeof(Nodo));
ins->data = data;
Nodo* itr = head;
//case: empty
if (head == NULL) {
ins->next = ins;
ins->prev = ins;
head = ins;
return;
}
//case: at begining
else if (head->data > data){
head->prev->next = ins;
ins->prev = head->prev;
ins->next = head;
head->prev = ins;
head = ins;
return;
}
else {
while (itr->data < data) {
// case: at end of list
if (itr->next == head) {
ins->next = head;
ins->prev = itr;
itr->next = ins;
head->prev = ins;
return;
}
else {
itr = itr->next;
}
}
// case: middle
itr->prev->next = ins;
ins->prev = itr->prev;
itr->prev = ins;
ins->next = itr;
return;
}
}
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