數據結構-線性表

 

線性表定義：
　　1、0個或多個元素的集合
　　2、元素之間是有序的
　　3、元素個數有限
　　4、元素數據的類型必須相同

線性表是相同類型的n個數據元素的有限序列。
逐項訪問，順序存儲
前驅 后繼

 

線性表在程序中表現為一種特殊的數據類型。

線性表的操作則表現為一組函數。

 

順序表（線性表的順序存儲結構）：

SeqList.h

#ifndef _SEQLIST_H_
#define _SEQLIST_H_

typedef void SeqList;
typedef void SeqListNode;

/*
    該方法用於創建並且返回一個空的線性表
*/
SeqList* SeqList_Create(int capacity);

/*
    該方法用於銷毀一個線性表list
*/
void SeqList_Destroy(SeqList* list);

/*
    該方法用於將一個線性表list中的所有元素清空
    使得線性表回到創建時的初始狀態
*/
void SeqList_Clear(SeqList* list);

/*
    該方法用於返回一個線性表list中的所有元素個數
*/
int SeqList_Length(SeqList* list);


/*
    返回線性表的最大容量 
*/ 
int SeqList_Capacity(SeqList* list);

/*
    該方法用於向一個線性表list的pos位置處插入新元素node
    返回值為1表示插入成功，0表示插入失敗
*/
int SeqList_Insert(SeqList* list, SeqListNode* node, int pos);

/*
    該方法用於獲取一個線性表list的pos位置處的元素
    返回值為pos位置處的元素，NULL表示獲取失敗
*/
SeqListNode* SeqList_Get(SeqList* list, int pos);

/*
    該方法用於刪除一個線性表list的pos位置處的元素
    返回值為被刪除的元素，NULL表示刪除失敗
*/
SeqListNode* SeqList_Delete(SeqList* list, int pos);

#endif

 

SeqList.c

#include <stdio.h>
#include <malloc.h>
#include "SeqList.h"

 /**
 頭文件中定義為void 
 實現時定義真實的類型
 
 數據封裝
 
 1、對外不用關心list,listNode的真實類型 
 2、不會產生誤操作 
 
 */
 
typedef unsigned int TSeqListNode; //存儲地址，這樣可以適用於任何數據類型，更通用 

typedef struct _tag_SeqList
{
    int capacity;
    int length;
    TSeqListNode* node;
} TSeqList;

SeqList* SeqList_Create(int capacity) // O(1)
{
    TSeqList* ret = NULL;
    
    if( capacity >= 0 )
    {
        //結構體本身+數組 
        ret = (TSeqList*)malloc(sizeof(TSeqList) + sizeof(TSeqListNode) * capacity);
    }
    
    if( ret != NULL )
    {
        ret->capacity = capacity;
        ret->length = 0;
        ret->node = (TSeqListNode*)(ret + 1);
    }
    
    return ret;
}

void SeqList_Destroy(SeqList* list) // O(1)
{
    free(list);
}

void SeqList_Clear(SeqList* list) // O(1)
{
    TSeqList* sList = (TSeqList*)list;
    
    if( sList != NULL )
    {
        sList->length = 0;
    }
}

int SeqList_Length(SeqList* list) // O(1)
{
    TSeqList* sList = (TSeqList*)list;
    int ret = -1;
    
    if( sList != NULL )
    {
        ret = sList->length;
    }
    
    return ret;
}

int SeqList_Capacity(SeqList* list) // O(1)
{
    TSeqList* sList = (TSeqList*)list;
    int ret = -1;
    
    if( sList != NULL )
    {
        ret = sList->capacity;
    }
    
    return ret;
}

// pos 從0開始算起 
int SeqList_Insert(SeqList* list, SeqListNode* node, int pos) // O(n) 
{
    TSeqList* sList = (TSeqList*)list;
    int ret = (sList != NULL);
    int i = 0;
    
    ret = ret && (sList->length + 1 <= sList->capacity);
    ret = ret && (0 <= pos);
    
    if( ret )
    {
        if( pos >= sList->length )
        {
            pos = sList->length;
        }
        
        for(i=sList->length; i>pos; i--)
        {
            sList->node[i] = sList->node[i-1];
        }
        
        sList->node[i] = (TSeqListNode)node;
        
        sList->length++;
    }
    
    return ret;
}

SeqListNode* SeqList_Get(SeqList* list, int pos) // O(1) 
{
    TSeqList* sList = (TSeqList*)list;
    SeqListNode* ret = NULL;
    
    if( (sList != NULL) && (0 <= pos) && (pos < sList->length) )
    {
        ret = (SeqListNode*)(sList->node[pos]);
    }
    
    return ret;
}

SeqListNode* SeqList_Delete(SeqList* list, int pos) // O(n)
{
    TSeqList* sList = (TSeqList*)list;
    SeqListNode* ret = SeqList_Get(list, pos);
    int i = 0;
    
    if( ret != NULL )
    {
        for(i=pos+1; i<sList->length; i++)
        {
            sList->node[i-1] = sList->node[i];
        }
        
        sList->length--;
    }
    
    return ret;
}

 

 

main.c

#include <stdio.h>
#include <stdlib.h>
#include "SeqList.h"

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char *argv[]) 
{
    SeqList* list = SeqList_Create(5);
    
    int i = 0;
    int j = 1;
    int k = 2;
    int x = 3;
    int y = 4;
    int z = 5;
    int index = 0;
    
   /**
   找不到  TSeqList 因為在 SeqList.c 中定義 
    TSeqList *a = (TSeqList*)list;
    a->length = 0;
   */
   
    // 由於list是void*類型，所以不被允許，更加安全 
      // list->length = 0; 
    
    SeqList_Insert(list, &i, 0);
    SeqList_Insert(list, &j, 0);
    SeqList_Insert(list, &k, 0);
    SeqList_Insert(list, &x, 0);
    SeqList_Insert(list, &y, 0);
    SeqList_Insert(list, &z, 0);
    
    for(index=0; index<SeqList_Length(list); index++)
    {
        int* p = (int*)SeqList_Get(list, index);
        
        printf("%d\n", *p);
    }
    
    printf("\n");
    
    while( SeqList_Length(list) > 0 )
    {
        int* p = (int*)SeqList_Delete(list, 0);
        
        printf("%d\n", *p);
    }
    
    SeqList_Destroy(list);
    
    return 0;
}

 

優點：

　　無需為線性表中的邏輯關系增加額外的空間

　　可以快速獲取表中合法位置的元素

缺點：

　　插入和刪除需要移動大量的元素。

　　當線性表長度變化較大時難以確定存儲空間的容量（浪費空間）。

 

單鏈表（線性表的鏈式存儲）

鏈式存儲定義：
　　為了表示每個數據元素與其后繼元素之間的邏輯關系，每個元素除了存儲本身的信息外，
　　還需要存儲其直接后續信息。

節點：數據域+指針域

n個節點鏈接成一個鏈式線性表的結構叫做鏈表。

當每個節點只包含一個指針域時，叫做單鏈表。

表頭節點：
　　鏈表中第一個節點（但不是數據元素）， 包含指向第一個數據元素的指針以及鏈表的一些自身信息.

數據節點：
　　鏈表中代表數據元素的節點, 包含指向下一個數據元素的指針和數據元素的信息。

尾節點：
　　鏈表中最后一個數據節點， 其下一元素指針為空，表示無后繼.


頭插法：每次都從鏈表頭部插入
尾插法：每次都從鏈表尾部插入

 

LinkList.c

#include <stdio.h>
#include <malloc.h>
#include "LinkList.h"

typedef struct _tag_LinkList
{
    LinkListNode header;
    int length;
} TLinkList;

LinkList* LinkList_Create() // O(1)
{
    TLinkList* ret = (TLinkList*)malloc(sizeof(TLinkList));
    
    if( ret != NULL )
    {
        ret->length = 0;
        ret->header.next = NULL;
    }
    
    return ret;
}

void LinkList_Destroy(LinkList* list) // O(1)
{
    free(list);
}

void LinkList_Clear(LinkList* list) // O(1)
{
    TLinkList* sList = (TLinkList*)list;
    
    if( sList != NULL )
    {
        sList->length = 0;
        sList->header.next = NULL;
    }
}

int LinkList_Length(LinkList* list) // O(1)
{
    TLinkList* sList = (TLinkList*)list;
    int ret = -1;
    
    if( sList != NULL )
    {
        ret = sList->length;
    }
    
    return ret;
}

int LinkList_Insert(LinkList* list, LinkListNode* node, int pos) // O(n)
{ 
    TLinkList* sList = (TLinkList*)list;
    int ret = (sList != NULL) && (pos >= 0) && (node != NULL);
    int i = 0;
    
    if( ret )
    {
        LinkListNode* current = (LinkListNode*)sList;
        
        for(i=0; (i<pos) && (current->next != NULL); i++)
        {
            current = current->next;
        }
        
        node->next = current->next;
        current->next = node;
        
        sList->length++;
    }
    
    return ret;
}

LinkListNode* LinkList_Get(LinkList* list, int pos) // O(n)
{
    TLinkList* sList = (TLinkList*)list; //轉換成不同的類型，則可以訪問不同的數據 
    LinkListNode* ret = NULL;
    int i = 0;
    
    if( (sList != NULL) && (0 <= pos) && (pos < sList->length) )
    {
        //轉換成不同的類型，則可以訪問不同的數據 
        LinkListNode* current = (LinkListNode*)sList;
        
        for(i=0; i<pos; i++)
        {
            current = current->next;
        }
        
        ret = current->next;
    }
    
    return ret;
}

LinkListNode* LinkList_Delete(LinkList* list, int pos) // O(n)
{
    TLinkList* sList = (TLinkList*)list;
    LinkListNode* ret = NULL;
    int i = 0;
    
    if( (sList != NULL) && (0 <= pos) && (pos < sList->length) )
    {
        LinkListNode* current = (LinkListNode*)sList;
        
        for(i=0; i<pos; i++)
        {
            current = current->next;
        }
        
        ret = current->next;
        current->next = ret->next;
        
        sList->length--;
    }
    
    return ret;
}

 

LinkList.h

#ifndef _LINKLIST_H_
#define _LINKLIST_H_

typedef void LinkList;
typedef struct _tag_LinkListNode LinkListNode;
struct _tag_LinkListNode
{
    LinkListNode* next;
};

LinkList* LinkList_Create();

void LinkList_Destroy(LinkList* list);

void LinkList_Clear(LinkList* list);

int LinkList_Length(LinkList* list);

int LinkList_Insert(LinkList* list, LinkListNode* node, int pos);

LinkListNode* LinkList_Get(LinkList* list, int pos);

LinkListNode* LinkList_Delete(LinkList* list, int pos);

#endif

 

main.c

#include <stdio.h>
#include <stdlib.h>
#include "LinkList.h"

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

struct Value
{
    LinkListNode header;
    int v;
};

int main(int argc, char *argv[]) 
{
    int i = 0;
    LinkList* list = LinkList_Create();
    
    struct Value v1;
    struct Value v2;
    struct Value v3;
    struct Value v4;
    struct Value v5;
    
    v1.v = 1;
    v2.v = 2;
    v3.v = 3;
    v4.v = 4;
    v5.v = 5;
    
    //尾插法建立鏈表
     
    LinkList_Insert(list, (LinkListNode*)&v1, LinkList_Length(list));
    LinkList_Insert(list, (LinkListNode*)&v2, LinkList_Length(list));
    LinkList_Insert(list, (LinkListNode*)&v3, LinkList_Length(list));
    LinkList_Insert(list, (LinkListNode*)&v4, LinkList_Length(list));
    LinkList_Insert(list, (LinkListNode*)&v5, LinkList_Length(list));
    
    for(i=0; i<LinkList_Length(list); i++)
    {
        struct Value* pv = (struct Value*)LinkList_Get(list, i);
        
        printf("%d\n", pv->v);
    }
    
    while( LinkList_Length(list) > 0 )
    {
        struct Value* pv = (struct Value*)LinkList_Delete(list, 0);
        
        printf("%d\n", pv->v);
    }
    
    LinkList_Destroy(list);
    
    return 0;
}

 

優點：
　　無需一次性定制鏈表的容量。
　　插入和刪除無需移動數據元素。

缺點：
　　數據元素必須保存后繼元素的位置信息。
　　獲取指定的數據元素操作需要順序訪問之前的元素。

　　單鏈表必須包含一個額外的指針域，沒有指針的程序無法實現。（有些語言沒有指針） 

 

靜態鏈表（單鏈表的數組方式實現）

靜態鏈表是順序表的改進，解決了順序表插入和刪除要移動大量元素的問題，同時解決了單鏈表必須依靠指針的問題。

靜態鏈表（在順序表的基礎上用數組實現的單鏈表）：

　　順序表中的元素由兩個元素組成：data和next
　　data用於存儲數據。
　　next用於存儲下一個元素在數組中的下標。

靜態鏈表主要用於不支持指針的程序數據語言。

靜態鏈表的實現是一種內存管理的有簡易方法。(類似 malloc， free功能)

 

StaticList.h

#ifndef _STATICLIST_H_
#define _STATICLIST_H_

typedef void StaticList;
typedef void StaticListNode;

StaticList* StaticList_Create(int capacity);

void StaticList_Destroy(StaticList* list);

void StaticList_Clear(StaticList* list);

int StaticList_Length(StaticList* list);

int StaticList_Capacity(StaticList* list);

int StaticList_Insert(StaticList* list, StaticListNode* node, int pos);

StaticListNode* StaticList_Get(StaticList* list, int pos);

StaticListNode* StaticList_Delete(StaticList* list, int pos);

#endif

 

StaticList.c

#include <stdio.h>
#include <malloc.h>
#include "StaticList.h"

#define AVAILABLE -1

typedef struct _tag_StaticListNode
{
    unsigned int data;
    int next; //數組下標 
} TStaticListNode;

typedef struct _tag_StaticList
{
    int capacity;
    TStaticListNode header; // 下面數組的第一個元素 
    TStaticListNode node[];
} TStaticList;

StaticList* StaticList_Create(int capacity) // O(n)
{
    TStaticList* ret = NULL;
    int i = 0;
    
    if( capacity >= 0 )
    {
        ret = (TStaticList*)malloc(sizeof(TStaticList) + sizeof(TStaticListNode) * (capacity + 1));
    }
    
    if( ret != NULL )
    {
        ret->capacity = capacity;
        ret->header.data = 0; // length, 復用頭結點  
        ret->header.next = 0; 
        
        for(i=1; i<=capacity; i++)
        {
            ret->node[i].next = AVAILABLE;
        }
    }
    
    return ret;
}

void StaticList_Destroy(StaticList* list) // O(1)
{
    free(list);
}

void StaticList_Clear(StaticList* list) // O(n)
{
    TStaticList* sList = (TStaticList*)list;
    int i = 0;
    
    if( sList != NULL )
    {
        sList->header.data = 0;
        sList->header.next = 0;
        
        for(i=1; i<=sList->capacity; i++)
        {
            sList->node[i].next = AVAILABLE;
        }
    }
}

int StaticList_Length(StaticList* list) // O(1)
{
    TStaticList* sList = (TStaticList*)list;
    int ret = -1;
    
    if( sList != NULL )
    {
        ret = sList->header.data;
    }
    
    return ret;
}

int StaticList_Capacity(StaticList* list) // O(1)
{
    TStaticList* sList = (TStaticList*)list;
    int ret = -1;
    
    if( sList != NULL )
    {
        ret = sList->capacity;
    }
    
    return ret;
}

int StaticList_Insert(StaticList* list, StaticListNode* node, int pos)  // O(n)
{
    TStaticList* sList = (TStaticList*)list;
    int ret = (sList != NULL);
    int current = 0;
    int index = 0; // 可利用下標 
    int i = 0;
    
    ret = ret && (sList->header.data + 1 <= sList->capacity);
    ret = ret && (pos >=0) && (node != NULL);
    
    if( ret )
    {
        // 尋找可以利用的位置 
        for(i=1; i<=sList->capacity; i++)
        {
            if( sList->node[i].next == AVAILABLE )
            {
                index = i;
                break;
            }
        }
        
        sList->node[index].data = (unsigned int)node;
        
        sList->node[0] = sList->header;
        
        for(i=0; (i<pos) && (sList->node[current].next != 0); i++)
        {
            current = sList->node[current].next;
        }
        
        sList->node[index].next = sList->node[current].next;
        sList->node[current].next = index;
        
        sList->node[0].data++;
        
        sList->header = sList->node[0];
    }
    
    return ret;
}

StaticListNode* StaticList_Get(StaticList* list, int pos)  // O(n)
{
    TStaticList* sList = (TStaticList*)list;
    StaticListNode* ret = NULL;
    int current = 0;
    int object = 0;
    int i = 0;
    
    if( (sList != NULL) && (0 <= pos) && (pos < sList->header.data) )
    {
        sList->node[0] = sList->header;
        
        for(i=0; i<pos; i++)
        {
            current = sList->node[current].next;
        }
        
        object = sList->node[current].next;
        
        ret = (StaticListNode*)(sList->node[object].data);
    }
    
    return ret;
}

StaticListNode* StaticList_Delete(StaticList* list, int pos) // O(n)
{
    TStaticList* sList = (TStaticList*)list;
    StaticListNode* ret = NULL;
    int current = 0;
    int object = 0;
    int i = 0;
    
    if( (sList != NULL) && (0 <= pos) && (pos < sList->header.data) )
    {
        sList->node[0] = sList->header;
        
        for(i=0; i<pos; i++)
        {
            current = sList->node[current].next;
        }
        
        object = sList->node[current].next;
        
        sList->node[current].next = sList->node[object].next;
        
        sList->node[0].data--;
        
        sList->header = sList->node[0];
        
        sList->node[object].next = AVAILABLE;
        
        ret = (StaticListNode*)(sList->node[object].data);
    }
    
    return ret;
}

 

main.c

#include <stdio.h>
#include <stdlib.h>
#include "StaticList.h"
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char *argv[])
{
    StaticList* list = StaticList_Create(10);
    
    int index = 0;
    
    int i = 0;
    int j = 1;
    int k = 2;
    int x = 3;
    int y = 4;
    int z = 5;
    
    StaticList_Insert(list, &i, 0);
    StaticList_Insert(list, &j, 0);
    StaticList_Insert(list, &k, 0);
    
    for(index=0; index<StaticList_Length(list); index++)
    {
        int* p = (int*)StaticList_Get(list, index);
        
        printf("%d\n", *p);
    }
    
    printf("\n");
    
    while( StaticList_Length(list) > 0 )
    {
        int* p = (int*)StaticList_Delete(list, 0);
        
        printf("%d\n", *p);
    }
    
    printf("\n");
    
    StaticList_Insert(list, &x, 0);
    StaticList_Insert(list, &y, 0);
    StaticList_Insert(list, &z, 0);
    
    printf("Capacity: %d Length: %d\n", StaticList_Capacity(list), StaticList_Length(list));
    
    for(index=0; index<StaticList_Length(list); index++)
    {
        int* p = (int*)StaticList_Get(list, index);
        
        printf("%d\n", *p);
    }
    
    StaticList_Destroy(list);
    
    return 0;
}

 

循環鏈表（單鏈表的擴展）

CircleList.h

 

#ifndef _CIRCLELIST_H_
#define _CIRCLELIST_H_

typedef void CircleList;
typedef struct _tag_CircleListNode CircleListNode;
struct _tag_CircleListNode
{
    CircleListNode* next;
};

CircleList* CircleList_Create();

void CircleList_Destroy(CircleList* list);

void CircleList_Clear(CircleList* list);

int CircleList_Length(CircleList* list);

int CircleList_Insert(CircleList* list, CircleListNode* node, int pos);

CircleListNode* CircleList_Get(CircleList* list, int pos);

CircleListNode* CircleList_Delete(CircleList* list, int pos);

CircleListNode* CircleList_DeleteNode(CircleList* list, CircleListNode* node);

CircleListNode* CircleList_Reset(CircleList* list);

CircleListNode* CircleList_Current(CircleList* list);

CircleListNode* CircleList_Next(CircleList* list);

#endif

 

 

CircleList.c

#include <stdio.h>
#include <malloc.h>
#include "CircleList.h"

typedef struct _tag_CircleList
{
    CircleListNode header;
    CircleListNode* slider; //游標 
    int length;
} TCircleList;

CircleList* CircleList_Create() // O(1)
{
    TCircleList* ret = (TCircleList*)malloc(sizeof(TCircleList));
    
    if( ret != NULL )
    {
        ret->length = 0;
        ret->header.next = NULL;
        ret->slider = NULL;
    }
    
    return ret;
}

void CircleList_Destroy(CircleList* list) // O(1)
{
    free(list);
}

void CircleList_Clear(CircleList* list) // O(1)
{
    TCircleList* sList = (TCircleList*)list;
    
    if( sList != NULL )
    {
        sList->length = 0;
        sList->header.next = NULL;
        sList->slider = NULL;
    }
}

int CircleList_Length(CircleList* list) // O(1)
{
    TCircleList* sList = (TCircleList*)list;
    int ret = -1;
    
    if( sList != NULL )
    {
        ret = sList->length;
    }
    
    return ret;
}

 
int CircleList_Insert(CircleList* list, CircleListNode* node, int pos) // O(n) 注： n並非鏈表的長度，而是插入的位置 
{ 
    TCircleList* sList = (TCircleList*)list;
    int ret = (sList != NULL) && (pos >= 0) && (node != NULL);
    int i = 0;
    
    if( ret )
    {
        CircleListNode* current = (CircleListNode*)sList;
        
        for(i=0; (i<pos) && (current->next != NULL); i++)
        {
            current = current->next;
        }
        
        node->next = current->next;
        current->next = node;
        
        //特殊判斷 構成環 
        if( sList->length == 0 )
        {
            sList->slider = node; // 游標默認指向第一個元素 
        }
        //特殊判斷

 if( current == (CircleListNode*)sList )//如果插入的是第一個元素，尾節點要指向新插入的元素
 {
　 　CircleListNode* last = CircleList_Get(sList, sList->length - 1);
　 　last->next = current->next;
 }

        sList->length++;
    }
    
    return ret;
}

CircleListNode* CircleList_Get(CircleList* list, int pos) // O(n)
{
    TCircleList* sList = (TCircleList*)list;
    CircleListNode* ret = NULL;
    int i = 0;
    
    if( (sList != NULL) && (pos >= 0) /*  可以轉圈  */ )
    {
        CircleListNode* current = (CircleListNode*)sList;
        
        for(i=0; i<pos; i++)
        {
            current = current->next;
        }
        
        ret = current->next;
    }
    
    return ret;
}

CircleListNode* CircleList_Delete(CircleList* list, int pos) // O(n)
{
    TCircleList* sList = (TCircleList*)list;
    CircleListNode* ret = NULL;
    int i = 0;
    
    if( (sList != NULL) && (pos >= 0)  && ( sList->length>0))
    {
        CircleListNode* current = (CircleListNode*)sList;
        CircleListNode* first = sList->header.next;
        CircleListNode* last = (CircleListNode*)CircleList_Get(sList, sList->length - 1);
        
        for(i=0; i<pos; i++)
        {
            current = current->next;
        }
        
        ret = current->next;
        current->next = ret->next;
        
        sList->length--;
        
        //刪除首元素時 
        if( first == ret )
        {
           // sList->header.next = ret->next; // @todo 
            last->next = ret->next; // @oops 刪除首元素時必須要手動處理環 
        }
        
        if( sList->slider == ret )
        {
            sList->slider = ret->next;
        }

        if( sList->length == 0 ) //@oops
        {
            sList->header.next = NULL; //鏈表變空時要手動 置為 null, 因為現在是環狀，不會存在null值 
            sList->slider = NULL;
        }
    }
    
    return ret;
}

CircleListNode* CircleList_DeleteNode(CircleList* list, CircleListNode* node) // O(n)
{
    TCircleList* sList = (TCircleList*)list;
    CircleListNode* ret = NULL;
    int i = 0;
    
    if( sList != NULL )
    {
        CircleListNode* current = (CircleListNode*)sList;
        
        for(i=0; i<sList->length; i++)
        {
            if( current->next == node )
            {
                ret = current->next;
                break;
            }
            
            current = current->next;
        }
        
        if( ret != NULL )
        {
            CircleList_Delete(sList, i);
        }
    }
    
    return ret;
}

CircleListNode* CircleList_Reset(CircleList* list) // O(1)
{
    TCircleList* sList = (TCircleList*)list;
    CircleListNode* ret = NULL;
    
    if( sList != NULL )
    {
        sList->slider = sList->header.next;
        ret = sList->slider;
    }
    
    return ret;
}

CircleListNode* CircleList_Current(CircleList* list) // O(1)
{
    TCircleList* sList = (TCircleList*)list;
    CircleListNode* ret = NULL;
    
    if( sList != NULL )
    {
        ret = sList->slider;
    }
    
    return ret;
}

CircleListNode* CircleList_Next(CircleList* list) // O(1)
{
    TCircleList* sList = (TCircleList*)list;
    CircleListNode* ret = NULL;
    
    if( (sList != NULL) && (sList->slider != NULL) )
    {
        ret = sList->slider;
        sList->slider = ret->next;
    }
    
    return ret;
}

 

main.c

#include <stdio.h>
#include <stdlib.h>
#include "CircleList.h"

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

struct Value
{
    CircleListNode header;
    int v;
};

int main(int argc, char *argv[])
{
    int i = 0;

    CircleList* list = CircleList_Create();
    
    struct Value v1;
    struct Value v2;
    struct Value v3;
    struct Value v4;
    struct Value v5;
    struct Value v6;
    struct Value v7;
    struct Value v8;
    
    
    v1.v = 1;
    v2.v = 2;
    v3.v = 3;
    v4.v = 4;
    v5.v = 5;
    v6.v = 6;
    v7.v = 7;
    v8.v = 8;
    
    CircleList_Insert(list, (CircleListNode*)&v1, CircleList_Length(list));
    CircleList_Insert(list, (CircleListNode*)&v2, CircleList_Length(list));
    CircleList_Insert(list, (CircleListNode*)&v3, CircleList_Length(list));
    CircleList_Insert(list, (CircleListNode*)&v4, CircleList_Length(list));
    
    CircleList_Insert(list, (CircleListNode*)&v5, 5);
    CircleList_Delete(list, 0);
    
    for(i=0; i<2*CircleList_Length(list); i++)
    {
        struct Value* pv = (struct Value*)CircleList_Get(list, i);
        
        printf("%d\n", pv->v);
    }
    
    printf("\n");
    
    while( CircleList_Length(list) > 0 )
    {
        struct Value* pv = (struct Value*)CircleList_Delete(list, 0);
        
        printf("%d\n", pv->v);
    }
    
   
   
    CircleList_Destroy(list);
    
    return 0;
}

 

循環鏈表是單鏈表基礎上的一個增強，可以完全替代單鏈表。

循環鏈表的next和current操作可以高效的遍歷鏈表中的所有元素。

 

 雙向鏈表：

單鏈表的數據元素無法直接訪問其前驅元素。
逆序訪問單鏈表的元素是極其耗時的。

雙向鏈表的定義：
　　在單鏈表節點中增加一個指向其前驅的pre指針

DLinkList.h

#ifndef _DLINKLIST_H_
#define _DLINKLIST_H_

typedef void DLinkList;
typedef struct _tag_DLinkListNode DLinkListNode;
struct _tag_DLinkListNode
{
    DLinkListNode* next;
    DLinkListNode* pre;
};

DLinkList* DLinkList_Create();

void DLinkList_Destroy(DLinkList* list);

void DLinkList_Clear(DLinkList* list);

int DLinkList_Length(DLinkList* list);

int DLinkList_Insert(DLinkList* list, DLinkListNode* node, int pos);

DLinkListNode* DLinkList_Get(DLinkList* list, int pos);

DLinkListNode* DLinkList_Delete(DLinkList* list, int pos);

DLinkListNode* DLinkList_DeleteNode(DLinkList* list, DLinkListNode* node);

DLinkListNode* DLinkList_Reset(DLinkList* list);

DLinkListNode* DLinkList_Current(DLinkList* list);

DLinkListNode* DLinkList_Next(DLinkList* list);

DLinkListNode* DLinkList_Pre(DLinkList* list);

#endif

DLinkList.c

#include <stdio.h>
#include <malloc.h>
#include "DLinkList.h"

typedef struct _tag_DLinkList
{
    DLinkListNode header;
    DLinkListNode* slider;
    int length;
} TDLinkList;

DLinkList* DLinkList_Create() // O(1)
{
    TDLinkList* ret = (TDLinkList*)malloc(sizeof(TDLinkList));
    
    if( ret != NULL )
    {
        ret->length = 0;
        ret->header.next = NULL;
        ret->header.pre = NULL;
        ret->slider = NULL;
    }
    
    return ret;
}

void DLinkList_Destroy(DLinkList* list) // O(1)
{
    free(list);
}

void DLinkList_Clear(DLinkList* list) // O(1)
{
    TDLinkList* sList = (TDLinkList*)list;
    
    if( sList != NULL )
    {
        sList->length = 0;
        sList->header.next = NULL;
        sList->header.pre = NULL;
        sList->slider = NULL;
    }
}

int DLinkList_Length(DLinkList* list) // O(1)
{
    TDLinkList* sList = (TDLinkList*)list;
    int ret = -1;
    
    if( sList != NULL )
    {
        ret = sList->length;
    }
    
    return ret;
}

int DLinkList_Insert(DLinkList* list, DLinkListNode* node, int pos) // O(n)
{ 
    TDLinkList* sList = (TDLinkList*)list;
    int ret = (sList != NULL) && (pos >= 0) && (node != NULL);
    int i = 0;
    
    if( ret )
    {
        DLinkListNode* current = (DLinkListNode*)sList;
        DLinkListNode* next = NULL;
        
        for(i=0; (i<pos) && (current->next != NULL); i++)
        {
            current = current->next;
        }
        
        next = current->next;
        
        current->next = node;
        node->next = next;
        
        //如果是空鏈表或最后一個元素則next沒有prev 
        if( next != NULL )
        {
            next->pre = node;
        }
        
        node->pre = current;
        
        //如果插入的是第一個元素，prev應為 NULL 
        if( sList->length == 0 )
        {
            sList->slider = node; //游標默認指向第一個元素 
        }

if( current == (CircleListNode*)sList )
{
　　CircleListNode* last = CircleList_Get(sList, sList->length - 1);
　　last->next = current->next;
}

        sList->length++;
    }
    
    return ret;
}

DLinkListNode* DLinkList_Get(DLinkList* list, int pos) // O(n)
{
    TDLinkList* sList = (TDLinkList*)list;
    DLinkListNode* ret = NULL;
    int i = 0;
    
    if( (sList != NULL) && (0 <= pos) && (pos < sList->length) )
    {
        DLinkListNode* current = (DLinkListNode*)sList;
        
        for(i=0; i<pos; i++)
        {
            current = current->next;
        }
        
        ret = current->next;
    }
    
    return ret;
}

DLinkListNode* DLinkList_Delete(DLinkList* list, int pos) // O(n)
{
    TDLinkList* sList = (TDLinkList*)list;
    DLinkListNode* ret = NULL;
    int i = 0;
    
    if( (sList != NULL) && (0 <= pos) && (pos < sList->length) )
    {
        DLinkListNode* current = (DLinkListNode*)sList;
        DLinkListNode* next = NULL;
        
        for(i=0; i<pos; i++)
        {
            current = current->next;
        }
        
        ret = current->next;
        next = ret->next;
        
        current->next = next;
        
        if( next != NULL )//刪除最后一個元素 
        {
            next->pre = current;
            
            //刪除第一個元素，第二元素的prev=null 
            if( current == (DLinkListNode*)sList )
            {
                next->pre = NULL;
            }
        }
        
        if( sList->slider == ret )
        {
            sList->slider = next;
        }
        
        sList->length--;
    }
    
    return ret;
}

DLinkListNode* DLinkList_DeleteNode(DLinkList* list, DLinkListNode* node)
{
    TDLinkList* sList = (TDLinkList*)list;
    DLinkListNode* ret = NULL;
    int i = 0;
    
    if( sList != NULL )
    {
        DLinkListNode* current = (DLinkListNode*)sList;
        
        for(i=0; i<sList->length; i++)
        {
            if( current->next == node )
            {
                ret = current->next;
                break;
            }
            
            current = current->next;
        }
        
        if( ret != NULL )
        {
            DLinkList_Delete(sList, i);
        }
    }
    
    return ret;
}

DLinkListNode* DLinkList_Reset(DLinkList* list)
{
    TDLinkList* sList = (TDLinkList*)list;
    DLinkListNode* ret = NULL;
    
    if( sList != NULL )
    {
        sList->slider = sList->header.next;
        ret = sList->slider;
    }
    
    return ret;
}

DLinkListNode* DLinkList_Current(DLinkList* list)
{
    TDLinkList* sList = (TDLinkList*)list;
    DLinkListNode* ret = NULL;
    
    if( sList != NULL )
    {
        ret = sList->slider;
    }
    
    return ret;
}

DLinkListNode* DLinkList_Next(DLinkList* list)
{
    TDLinkList* sList = (TDLinkList*)list;
    DLinkListNode* ret = NULL;
    
    if( (sList != NULL) && (sList->slider != NULL) )
    {
        ret = sList->slider;
        sList->slider = ret->next;
    }
    
    return ret;
}

DLinkListNode* DLinkList_Pre(DLinkList* list)
{
    TDLinkList* sList = (TDLinkList*)list;
    DLinkListNode* ret = NULL;
    
    if( (sList != NULL) && (sList->slider != NULL) )
    {
        ret = sList->slider;
        sList->slider = ret->pre;
    }
    
    return ret;
}

main.c

#include <stdio.h>
#include <stdlib.h>
#include "DLinkList.h"
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

struct Value
{
    DLinkListNode header;
    int v;
};

int main(int argc, char *argv[])
{
    int i = 0;
    DLinkList* list = DLinkList_Create();
    struct Value* pv = NULL;
    struct Value v1;
    struct Value v2;
    struct Value v3;
    struct Value v4;
    struct Value v5;
    
    v1.v = 1;
    v2.v = 2;
    v3.v = 3;
    v4.v = 4;
    v5.v = 5;
    
    DLinkList_Insert(list, (DLinkListNode*)&v1, DLinkList_Length(list));
    DLinkList_Insert(list, (DLinkListNode*)&v2, DLinkList_Length(list));
    DLinkList_Insert(list, (DLinkListNode*)&v3, DLinkList_Length(list));
    DLinkList_Insert(list, (DLinkListNode*)&v4, DLinkList_Length(list));
    DLinkList_Insert(list, (DLinkListNode*)&v5, DLinkList_Length(list));
    
    for(i=0; i<DLinkList_Length(list); i++)
    {
        pv = (struct Value*)DLinkList_Get(list, i);
        
        printf("%d\n", pv->v);
    }
    
    printf("\n");
    
    DLinkList_Delete(list, DLinkList_Length(list)-1);
    DLinkList_Delete(list, 0);
    
    for(i=0; i<DLinkList_Length(list); i++)
    {
        pv = (struct Value*)DLinkList_Next(list);
        
        printf("%d\n", pv->v);
    }
    
    printf("\n");
    
    DLinkList_Reset(list);
    DLinkList_Next(list);
    
    pv = (struct Value*)DLinkList_Current(list);
    
    printf("%d\n", pv->v);
    
    DLinkList_DeleteNode(list, (DLinkListNode*)pv);
    
    pv = (struct Value*)DLinkList_Current(list);
    
    printf("%d\n", pv->v);
    
    DLinkList_Pre(list);
    
    pv = (struct Value*)DLinkList_Current(list);
    
    printf("%d\n", pv->v);
    
    printf("Length: %d\n", DLinkList_Length(list));
    
    DLinkList_Destroy(list);
    
    return 0;
}