链表的常见操作

链表

文章目录

• 链表
• • 创建链表
  • • • 单链表
      • • 实现
        • 错例
    • 循环链表
    • • 单独创建
      • 逐节点创建
      • 约瑟夫环问题
  • 删除节点
  • • 实现方式一：
    • 实现方式二：
    • 删除节点并建立新链表
  • 逆置链表
  • • 实现：
  • 链表排序

struct List
{
	int data;
	struct List* next;
}

创建链表

单链表

实现

struct List* listCreate()
{
	int data;
    struct List* head = NULL;
    struct List* pre = NULL;
    struct List* current = NULL;
    
    while(scanf("%d",&data) && data != -1)
    {
        current = (struct List*)malloc(sizeof(struct List));
        if(head == NULL)
            head = current;
        else
            pre->next = current;
        current->next = NULL;
        current->data = data;
        pre = current;
    }
    return head;
}

错例

struct List* listCreate()
{
	int data;;
	struct List* current = NULL;
	struct List* head = current;
	while (scanf("%d", &data) && data != -1)
	{
		current = (struct List*)malloc(sizeof(struct List));
		if (head == NULL)
			head = current;
		current->data = data;
		current = current->next;
	}
	return head;
}

在使用malloc函数开辟的空间中，不要进行指针的移动，因为一旦移动之后可能出现申请的空间和释放空间大小的不匹配

循环链表

单独创建

struct List* circle_listCreate()
{
	int data;
    struct List* head = NULL;
    struct List* pre = NULL;
    struct List* current = NULL;
    
    while(scanf("%d",&data) && data != -1)
    {
        current = (struct List*)malloc(sizeof(struct List));
        if(head == NULL)
            head = current;
        else
            pre->next = current;
        current->next = head;
        current->data = data;
        pre = current;
    }
    return head;
}

逐节点创建

void Append(struct List** L,int data)
{
    struct List* head = *L;
    struct List* newNode = NULL;
    if((*L) == NULL)
    {
        (*L) = (struct List*)malloc(sizeof(struct List));
        (*L)->data = data;
        head = (*L);
        (*L)->next = head;
    }
    else
    {
        while ((*L)->next != head){
            (*L) = (*L)->next;
        }
        newNode = (struct List*)malloc(sizeof(struct List));
        newNode->data = data;
        (*L)->next = newNode;
        newNode->next = head;
        *L = head;
    }
}

约瑟夫环问题

void Append(struct List** L,int data)
{
    struct List* head = *L;
    struct List* newNode = NULL;
    if((*L) == NULL)
    {
        (*L) = (struct List*)malloc(sizeof(struct List));
        (*L)->data = data;
        head = (*L);
        (*L)->next = head;
    }
    else
    {
        while ((*L)->next != head){
            (*L) = (*L)->next;
        }
        newNode = (struct List*)malloc(sizeof(struct List));
        newNode->data = data;
        (*L)->next = newNode;
        newNode->next = head;
        *L = head;
    }
}
void Display(struct List* L,int num)
{
    struct List* head = L;
    struct List* pre = NULL;
    struct List* kill = NULL;
    int nodeNum = 0;
    while (L->next != head)
    {
        nodeNum++;
        L = L->next;
    }
    pre = L;
    L = L->next;
    nodeNum++;
    while (nodeNUm)
    {
        if (nodeNum == 1)
        {
            printf("%d",L->data);
            free(L);
            return;
        }
        for (int i=1; i < m; i++)
        {
            pre = L;
            L = L->next;
        }
        printf("%d ", L->data);
        kill = L;
        L = L->next;
        free(kill);
        nodeNum--;
    }
}

删除节点

实现方式一：

struct list* listDelete(struct list* L,int data)
{
    struct list* pre = L;
    struct list* head = L;
    struct list* kill;
    
    while(head != NULL && head->data == m)
    {
        kill = head;
        head = head->next;
        free(kill);
    }
    if(head == NULL)
        return head;
    
    pre = head;
    kill = head->next;
    while(kill!=NULL)
    {
        if(kill->data == m)
        {
            pre->next = kill->next;
            free(kill);
            kill = pre->next;
        }
        else
        {
            pre = kill;
            kill = kill->next;
        }
    }
    return head;
}

实现方式二：

struct list* listDelete(struct list** L,int data)
{
    struct list* head = (*L), * pre = (*L);
    struct list* newL = *L;
    struct list* kill = NULL;
    while (*L !- NULL)
    {
        if((*L)->data == data)
        {
            if((*L) == newL)
                newL == newL->next;
            else
                pre->next = (*L)->next;
            kill = (*L);
            (*L) = (*L)->next;
            free(kill);
        }
        else
        {
            pre = (*L);
            (*L) = (*L)->next;
        }
    }
    *L = newL;
    return head;
}

删除节点并建立新链表

struct list* list_Delete_Create(struct list** L) //数据为奇数存为新链表
{
    struct list* newhead = NULL, * newcurrent = NULL, * newpre = NULL;
    struct list* newL = *L;
    struct list* kill = NULL;
    struct list* pre = *L;
    while (*L)
    {
        if((*L)->data%2 == 1)
        {
            newcurrent = (struct list*)malloc(sizeof(struct list));
            if(newhead == NULL)
                newhead = newcurrent;
            else
                newpre->next = newcurrent;
            newcurrent->data = (*L)->data;
            newcurrent->next = NULL;
            newpre = newcurrent;
            
            if((*L) == newL)
                newL = newL->next;
            else
                pre-next = (*L)->next;
            kill = (*L);
            (*L)=(*L)->next;
            free(kill);
        }
        else
        {
            pre = (*L);
            (*L) = (*L)->next;
        }
    }
    *L = newL;
    return newhead;
}

逆置链表

实现：

struct list* reverse(struct list* L)
{
    struct list* newhead = NULL, * current;
    while (L != NULL)
    {
        current = (struct list*)malloc(sizeof(struct list));
        current->data = L->data;
        L = L->next;
        current->next = newhead;
        newhead = current;
    }
    free(L);
    return newhead;
}

链表排序