第九课，静态链表

专题三：渐入佳境。包括以下章节：

1. 无招胜有招-静态链表
2. 气宗门道-循环链表
3. 剑宗门道-双向链表
4. 课后练习

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思考

单链表完美解决了顺序表的问题！还有其它改进顺序表的方法吗？

单链表的相对劣势

单链表的实现严重依赖指针！
数据元素中必须包含一个额外的指针域！
没有指针的程序设计语言无法实现！

顺序表的改进

静态链表的定义

• 顺序表数组中的元素由两个数据域组成：data和next
• data域用于存储数据
• next域用于存储下一个元素在数组中的下标

静态链表的逻辑结构

静态链表是在顺序表的基础上利用数组实现的单链表！

静态链表相关定义

结点结构体定义

typedef struct _tag_StaticListNode{    unsigned int data;    int next;}TStaticListNode;

静态链表结构体定义

typedef struct _tag_StaticList{    int capacity;    TStaticListNode header;    TStaticListNode node[];}TStaticList;

静态链表操作

1.获取第pos个元素操作

• 判断线性表是否合法
• 判断位置是否合法
• 由表头开始通过next域移动pos次后，当前元素的next域即要获取元素在数组中的下标

sList->node[0] = sList->header;for(i=0;i<pos;i++){    current = sList->node[current].next;}object = sList->node[current].next;

2.插入元素到位置pos操作

• 判断线性表是否合法
• 判断插入位置是否合法
• 在数组中查找空闲位置index
• 由表头开始通过next域移动pos次后，当前元素的next域为要插入的位置
• 将新元素插入
• 线性表长度加1

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

3.删除第pos个元素操作

• 判断线性表是否合法
• 判断删除位置是否合法
• 获取第pos个元素
• 将第pos个元素从链表中删除
• 线性表长度减1

小结

1. 静态链表其实是单链表的另一种实现方式
2. 静态链表的实现“媒介”不是指针而是数组
3. 静态链表主要用于不支持指针的程序设计语言中
4. 静态链表的实现是一种内存管理的简易方法

创建可复用静态链表

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 -1typedef struct _tag_StaticListNode{    unsigned int data;    int next;} TStaticListNode;typedef struct _tag_StaticList{    int capacity;    TStaticListNode header;    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;        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;    int i = 0;    ret = ret && (sList->header.data + 1 <= sList->capacity);    ret = ret && (pos >=0) && (node != NULL);    if( ret )    {        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;}