Question

我正在尝试实现一个代码，将包含整数变量的节点插入到双向链表中，该列表已经排序或者没有元素。我已经提供了一个文件来测试我的代码是否有效。我的代码编译得很好，只是测试每次都失败了我的代码。

这是我的排序插入的代码

void List<T>::insertSorted(T item)
{
    ListItem<T> *temp, *temp2;
    ListItem<T>* a=new ListItem<T>(item);   //creates a node with our input item

    if(head==NULL)
    {
        head=a;              //if the list is empty, set head equal to the new
        //node
    }


    //Following two conditions check whether head is the sole item in the list
    //(i.e head->next==NULL), and then insert our node in it accordingly.

    else if(head->value > item && head->next==NULL) 
    {
        a->next=head;
        head->prev=a;
        head=a;
    }

    else if(head->value < item  && head->next==NULL)
    {
        head->next=a;
        a->prev=head;
    }

    //This piece checks whether our list has more than one nodes, and adds
    //the input node accordingly.
    else if(head->next!=NULL)
    {
        temp=head->next;   //here i'm taking two consecutive nodes
        //which in the first case are head->next and head;
        temp2=head;
        while(temp!=NULL)
        {
            //if our value can be sandwiched between two nodes then do this
            if(temp->value > item && temp2->value < item)
            {
                temp2->next=a;
                a->prev=temp2;
                a->next=temp;
                temp->prev=a;
                break;
            }
            //go to the next two consecutive nodes
            temp=temp->next;
            temp2=temp2->next;

            //if one of our node is null (i.e we've reached the end of
            //the list, do the following
            if(temp2->value <= item && temp==NULL)
            {
                temp2->next=a;
                a->prev=temp2;
                break;
            }
        }

    }

}

这显然是错的。我在这里做错了什么？

Answer 1

您不是直接在函数中NULL next prev和a新节点else if(head->value == item && head->next==NULL) { head->next=a; a->prev=head; } //This piece checks whether our list has more than one nodes, and adds //the input node accordingly. else if(head->next!=NULL) { temp=head; temp2=head; //keep track of previous element in the loop while(temp!=NULL) { //if our value can be sandwiched between two nodes then do this if(temp->value < item) { temp2 = temp; temp = temp ->next; } else { //from temp onward all numbers will be grater than item. so inserting before item a->next = temp; a->prev = temp->prev; temp->prev = a; if (temp == head) { head = a; } else// if temp not head then there is a previous element assign previos elemnts next to a { temp2->next = a; } break; } } if (temp == NULL) { temp2->next=a; a->prev = temp2; } }指针。在insertSorted函数中进行修改后，代码可以完美地为我工作

if(head->value == item && head->next==NULL)

请检查

我发现的唯一问题是没有检查此情况{{1}}

在双向链表中排序插入

1 个答案: