链表的常见操作

#include<iostream>
#include<cstdio>
#include<cstdlib>
using namespace std;

typedef struct NodeType
{
    char elem;
    struct NodeType *next;
}Node;

typedef struct DNodetype
{
    char elem;
    struct DNodetype *prev;
    struct DNodetype *next;
}DNode;

/*创建单链表*/
Node *CreateList(Node *head)
{
    if(NULL == head)
    {
        head = (Node *)malloc(sizeof(Node));
        head->next = NULL;
    }

    Node *current = head, *temp;
    char ch;

    while(1)
    {
        cout<<"input elem(end of by '#'): ";
        cin>>ch;
        if('#' == ch)
            break;
        temp = (Node *)malloc(sizeof(Node));
        temp->elem = ch;
        temp->next = NULL;
        current->next = temp;
        current = temp;
    }

    return head;
}

/*创建双链表*/
DNode *CreateDlist(DNode *head)
{
    if(NULL == head)
    {
        head = (DNode *)malloc(sizeof(DNode));
        head->next = NULL;
    }

    DNode *current = head, *temp;
    char ch;

    while(1)
    {
        cout<<"input elem: ";
        cin>>ch;
        if('#' == ch)
            break;
        temp = (DNode *)malloc(sizeof(DNode));
        temp->elem = ch;
        temp->next = NULL;
        current->next = temp;
        temp->prev = current;
        current = temp;
    }

    return head;
}

/*创建循环单链表*/
Node *CycleList(Node *head)
{
    if(NULL == head)
    {
        head = (Node *)malloc(sizeof(Node));
        head->next = NULL;
    }

    Node *current = head, *temp;
    char ch;

    while(1)
    {
        cout<<"input elem(end of by '#'): ";
        cin>>ch;
        if('#' == ch)
            break;
        temp = (Node *)malloc(sizeof(Node));
        temp->elem = ch;
        temp->next = NULL;
        current->next = temp;
        current = temp;
    }
    current->next = head;

    return head;
}

/*打印单链表*/
void PrintList(Node *head)
{
    int n = 0;
    Node *current = head->next;
    cout<<"List are: ";
    while(NULL != current)
    {
        cout<<current->elem<<' ';
        current = current->next;
    }
    cout<<endl;
}

/*在单链表的末尾插入元素*/
void *InsertNode(Node *head, char elem)
{
    if(NULL == head)
        return head;

    Node *current = head->next;
    Node *prev = head;
    Node *temp;

    while(NULL != current)
    {
        prev = current;
        current = current->next;
    }

    temp = (Node *)malloc(sizeof(Node));
    temp->elem = elem;
    temp->next = NULL;
    prev->next = temp;

    return head;
}

/*删除单链表中某个元素*/
Node *DelNode(Node *head, char elem)
{
    if(NULL == head || NULL == head->next)
        return head;

    Node *prev = head, *current = head->next;

    while(NULL != current)
    {
        if(current->elem == elem)
        {
            prev->next = current->next;
            free(current);
            return head;
        }
        prev = current;
        current = current->next;
    }

    return head;
}

/*单链表逆置*/
Node *ReverseList(Node *head)
{
    if(NULL == head || NULL == head->next || NULL == head->next->next)
        return head;

    Node *current = head->next, *temp;
    head->next = NULL;

    while(NULL != current)
    {
        temp = current->next;
        current->next = head->next;
        head->next = current;
        current = temp;
    }

    return head;
}

/*求单链表的中间节点*/
Node *MiddleList(Node *head)
{
    if(NULL == head || NULL == head->next)
        return head;
    Node *middle = head, *last = head;

    while(NULL != last->next)
    {
        last = last->next;
        if(NULL != last->next)  
            last = last->next;
        middle = middle->next;
    }
    return middle;
}

/*合并有序单链表*/
Node *MergeList(Node *h1, Node *h2)
{
    if(NULL == h1 || NULL == h2 || NULL == h2->next)
        return h1;
    if(NULL == h1->next)
        return h2;
    Node *curr1, *curr2, *prev1, *temp;

    prev1 = h1;
    curr1 = h1->next;
    curr2 = h2->next;
    temp = h2;

    while(curr2)
    {
        while(curr1 && curr1->elem < curr2->elem)
        {
            prev1 = curr1;
            curr1 = curr1->next;
        }
        temp = curr2->next;
        prev1->next = curr2;
        curr2->next = curr1;

        curr1 = curr2;
        curr2 = temp;
    }

    return h1;
}

/*判断链表是否有环*/
int isCycleList(Node *head)
{
    if(NULL == head || NULL == head->next)
        return 0;
    Node *current = head;

    while(current)
    {
        if(current->next == head)
            return 1;
        current = current->next;
    }

    return 0;
}

int main()
{
    //freopen("in.txt", "r", stdin);
    //Node *head = NULL;
    //Node *head2 = NULL;
    //head = (Node *)malloc(sizeof(Node));

    //head = CreateList(head);
    //PrintList(head);

    //head2 = CreateList(head2);
    //PrintList(head2);


    //ReverseList(head);
    //PrintList(head);

    //InsertNode(head, '8');
    //PrintList(head);

    //DelNode(head, 'l');
    //PrintList(head);

    //head2 = CycleList(head2);
    //PrintList(head2);

    //printf("%c\n", MiddleList(head)->elem);

    //PrintList(MergeList(head, head2));

    //printf("%d\n", isCycleList(head));

    return 0;
}