线性表
线性表（linear list）是n个具有相同特性的数据元素的有限序列。 线性表是一种在实际中广泛使用的数据结构，常见的线性表：顺序表、链表、栈、队列、字符串…
链表
- 链式存储：用一组任意的存储单元来存储线性表
- 链表：采用链式存储方法的线性表称为链表
- 节点间的逻辑关系由存储节点中的指针实现
- 链表的结点由两部分构成：数据域和链域 链表的分类
链表的分类
单链表
单链表相关概念
单链表的两种形式
1.无头结点示意图
2.有头结点示意图
- 头指针：指向链表中第一个结点（头结点或者首元结点）
- 头结点：是在首元结点之前附设的一个结点；数据域内可存放链表长度等信息，它不计入表长度
- 首元结点：是指链表中第一个结点
结点结构
图示法表示单链表
需要明白的链表中结点间的逻辑关系
这里的p指针代表的就是首元结点，q指针代表的是首元结点的直接后继
空表如何表示？
无头结点
当头指针的值为空时，表示空表
有头结点
头结点的指针域为空时表示空表
单链表实现
1.表结点的设计
typedef int ET;
typedef struct Node
{
ET data; //用于存储数据
Node* next; //用于存储下个节点的地址
}Node;
typedef Node* List;
2.建立单链表
从一个空表开始,重复读入数据,生成新结点,将读入数据存放在新结点的数据域,然后将新结点插入当前链表中,直到结束。
有头结点情况下
(1).头插法
头插法建表：将新结点插入到当前链表的表头结点之后
参考源码
void linkedListCreateWithHeadNodeFromHead(List* phead){
assert(phead != NULL);
*phead = (Node*)malloc(sizeof(Node));
assert(phead != NULL);
(*phead)->data = -1;
(*phead)->next = NULL;
int i = 1;
for (; i <= 10; i++)
{
Node* s = (Node*)malloc(sizeof(Node));
assert(s != NULL);
s->data = i;
s->next = (*phead)->next;
(*phead)->next = s;
}
}
(2).尾插法
尾插法建表：将新结点插入到当前链表的表尾
参考源码
void linkedListCreateWithHeadNodeFromTail(List* phead){
assert(phead != NULL);
*phead = (Node*)malloc(sizeof(Node));
assert(phead != NULL);
(*phead)->data = -1;
(*phead)->next = NULL;
Node *p = *phead;
int i = 1;
for (; i <= 10; i++)
{
Node* s = (Node*)malloc(sizeof(Node));
assert(s != NULL);
s->data = i;
s->next = NULL;
p->next = s;
p = s;
}
}
无头结点情况下
(1).头插法参考源码
void linkedListCreateWithoutHeadNodeFromHead(List* phead){
assert(phead != NULL);
*phead = (Node*)malloc(sizeof(Node));
assert(phead != NULL);
(*phead)->data = 1;
(*phead)->next = NULL;
int i = 2;
for (; i <= 10; i++){
Node* s = (Node*)malloc(sizeof(Node));
assert(s != NULL);
s->data = i;
s->next = *phead;
*phead = s;
}
}
(2).尾插法参考源码
void linkedListCreateWithoutHeadNodeFromTail(List* phead){
assert(phead != NULL);
*phead = (Node*)malloc(sizeof(Node));
assert(*phead != NULL);
(*phead)->data = 1;
(*phead)->next = NULL;
Node* p = *phead;
for (int i = 2; i <= 10; i++)
{
Node* s = (Node*)malloc(sizeof(Node));
assert(s != NULL);
s->data = i;
s->next = NULL;
p->next = s;
p = s;
}
}
3.单向链表具体操作
下面的源码中一共实现了以下功能：
【1】初始化链表
【2】头插数据
【3】尾插数据
【4】获取首元结点
【5】获取末尾结点
【6】获取表长度
【7】删除首元结点
【8】删除末尾结点
【9】排序
【10】按值得大小插入数据
【11】按位置插入数据
【12】按值删除第一个数据
【13】按位置删除数据
【14】反转链表
【15】展示数据
【16】清空链表
【17】摧毁链表
【18】全表彻底删除某一个值
方法声明
void linkedListInitial(List* phead); //初始化链表
void linkedListWithoutHeadNodeAddFromHead(List* phead, ET val); //头插法
void linkedListWithoutHeadNodeAddFromTail(List* phead, ET val); //尾插法
Node* linkedLIstWithoutHeadNodeGetHead(List* phead); //获取头结点
Node* linkedListWithoutHeadNodeGetTail(List* phead); //获取尾结点
int linkedListWithoutHeadNodeGetLength(List* phead); //获取表长度
void linkedListWithoutHeadNodeDropHead(List* phead); //删除头结点
void linkedListWithoutHeadNodeDropTail(List* phead); //删除尾节点
void linkedListWithoutHeadNodeSortByValue(List* phead); //排序
void linkedListWithoutHeadNodeInsertByValue(List* phead, ET val); //按值插入
void linkedListWithoutHeadNodeInsertByPosition(List* phead, int pos, ET val); //按位置插入
void linkedListWithoutHeadNodeDropByValue(List* phead, ET val); //按值删除
void linkedListWithoutHeadNodeDropByPosition(List* phead, int pos, ET val); //按位置删除
void linkedListWithoutHeadNodeReverseList(List* phead); //反转链表
void linkedListWithoutHeadNodeShowData(List* phead); //展示数据
void linkedListWithoutHeadNodeClearList(List* phead); //清空链表
void linkedListWithoutHeadNodeDestroyList(List* phead); //摧毁链表
void linkedListWithoutHeadNodeEraseByValue(List* phead, ET val); //全表彻底删除某一个值
方法实现
void linkedListInitial(List* phead){
assert(phead != NULL);
*phead = NULL;
}
void linkedListWithoutHeadNodeAddFromHead(List* phead, ET val){
assert(phead != NULL);
Node* s = (Node*)malloc(sizeof(Node));
assert(s != NULL);
s->data = val;
s->next = *phead;
*phead = s;
}
void linkedListWithoutHeadNodeAddFromTail(List* phead, ET val){
assert(phead != NULL);
Node* p = *phead;
if (p == NULL){
//表为空时
*phead = (Node*)malloc(sizeof(Node));
assert(*phead != NULL);
(*phead)->data = val;
(*phead)->next = NULL;
}
else{
//表非空时
Node* s = (Node*)malloc(sizeof(Node));
assert(s != NULL);
s->data = val;
s->next = NULL;
while (p->next != NULL){
p = p->next;
}
p->next = s;
}
}
Node* linkedLIstWithoutHeadNodeGetHead(List* phead)
{
assert(phead != NULL);
if ((*phead) == NULL){
return NULL;
}
else{
return (*phead);
}
}
Node* linkedListWithoutHeadNodeGetTail(List* phead){
assert(phead != NULL);
if ((*phead) == NULL){
return NULL;
}
else{
Node* p = *phead;
while (p->next != NULL){
p = p->next;
}
return p;
}
}
int linkedListWithoutHeadNodeGetLength(List* phead){
assert(phead != NULL);
if ((*phead) == NULL) return 0;
int length = 1;
Node* p = *phead;
while (p->next != NULL){
length++;
p = p->next;
}
return length;
}
void linkedListWithoutHeadNodeDropHead(List* phead){
assert(phead != NULL);
if ((*phead) == NULL){
printf("表已空！无法删除！\n");
return;
}
Node *p = *phead;
if (p->next == NULL){
(*phead) = NULL;
free(p);
}
else{
(*phead) = p->next;
free(p);
}
printf("首元结点已删除！\n");
}
void linkedListWithoutHeadNodeDropTail(List* phead){
assert(phead != NULL);
if ((*phead) == NULL){
printf("表已空！无法删除！\n");
return;
}
Node *p = *phead;
if (p->next == NULL){
(*phead) = NULL;
free(p);
}
else{
while (p->next->next != NULL){
p = p->next;
}
Node *q = p->next;
free(q);
p->next = NULL;
}
printf("末尾结点已删除！\n");
}
void linkedListWithoutHeadNodeSortByValue(List* phead){
assert(phead != NULL);
if ((*phead) == NULL){
printf("表已空！无法排序！\n");
return;
}
if ((*phead)->next == NULL) return; //一个结点
Node* p = (*phead)->next;
Node* q = (*phead)->next;
(*phead)->next = NULL;
while (q != NULL){
q = q->next;
if ((*phead)->data < p->data){
Node* temp = *phead;
while (temp->next != NULL && temp->next->data < p->data){
temp = temp->next;
}
p->next = temp->next;
temp->next = p;
}
else{
p->next = *phead;
*phead = p;
}
p = q;
}
}
void linkedListWithoutHeadNodeInsertByValue(List* phead, ET val)
{
assert(phead != NULL);
if ((*phead) == NULL){
//表空时
linkedListWithoutHeadNodeAddFromHead(phead, val);
printf("按值插入数据完成！\n");
return;
}
linkedListWithoutHeadNodeSortByValue(phead);
Node* s = (Node*)malloc(sizeof(Node));
s->data = val;
s->next = NULL;
if ((*phead)->next == NULL && (*phead)->data > val){
//表中只有一个大于val的结点时
s->next = *phead;
*phead = s;
printf("按值插入数据完成！\n");
return;
}
Node* p = *phead;
while (p->next != NULL && p->next->data < val){
p = p->next;
}
s->next = p->next;
p->next = s;
printf("按值插入数据完成！\n");
}
void linkedListWithoutHeadNodeInsertByPosition(List* phead, int pos, ET val){
assert(phead != NULL);
int len = linkedListWithoutHeadNodeGetLength(phead);
if (pos <= 0 || pos > len){
printf("插入位置不合法！\n");
return;
}
int position = pos;
position--;
Node* s = (Node*)malloc(sizeof(Node));
s->data = val;
s->next = NULL;
if (position == 0){
linkedListWithoutHeadNodeAddFromHead(phead, val);
printf("已在%d位置上插入%d\n", pos, val);
return;
}
Node* p = *phead;
while (position != 1){
p = p->next;
position--;
}
s->next = p->next;
p->next = s;
printf("已在%d位置上插入%d\n", pos, val);
}
void linkedListWithoutHeadNodeDropByValue(List* phead, ET val){
assert(phead != NULL);
if ((*phead) == NULL){
printf("空表无法删除\n");
return;
}
linkedListWithoutHeadNodeSortByValue(phead);
Node* p = *phead;
if (p->data == val){
*phead = p->next;
free(p);
printf("第一次出现的%d这个数据已被删除!\n", val);
return;
}
while (p->next != NULL){
if (p->next->data == val){
Node* q = p->next;
p->next = q->next;
free(q);
printf("第一次出现的%d这个数据已被删除!\n", val);
return;
}
p = p->next;
}
printf("没有%d这个数据!\n", val);
}
void linkedListWithoutHeadNodeDropByPosition(List* phead, int pos){
assert(phead != NULL);
int len = linkedListWithoutHeadNodeGetLength(phead);
if (pos <= 0 || pos > len){
printf("删除位置不合法！\n");
return;
}
int position = pos;
position--;
if (position == 0){
linkedListWithoutHeadNodeDropHead(phead);
printf("已删除%d位置上的数据！\n", pos);
return;
}
if (position == len){
linkedListWithoutHeadNodeGetTail(phead);
}
Node* p = *phead;
while (position != 1){
p = p->next;
position--;
}
Node* s = p->next;
p->next = s->next;
free(s);
printf("已删除%d位置上的数据！\n", pos);
}
void linkedListWithoutHeadNodeReverseList(List* phead){
assert(phead != NULL);
if ((*phead)->next == NULL){
printf("逆置完成！\n");
return;
}
Node* p = (*phead)->next;
Node* q = (*phead)->next;
(*phead)->next = NULL;
while (q != NULL){
q = q->next;
p->next = *phead;
*phead = p;
p = q;
}
printf("逆置完成！\n");
}
void linkedListWithoutHeadNodeShowData(List phead){
Node *p = phead;
while (p != NULL){
printf("%d--->", p->data);
p = p->next;
}
printf("Over\n");
}
void linkedListWithoutHeadNodeClearList(List* phead){
assert(phead != NULL);
Node* p = *phead;
while ((*phead) != NULL){
*phead = p->next;
free(p);
p = *phead;
}
}
void linkedListWithoutHeadNodeDestroyList(List* phead){
assert(phead != NULL);
Node* p = *phead;
while ((*phead) != NULL){
*phead = p->next;
free(p);
p = *phead;
}
}
void linkedListWithoutHeadNodeEraseByValue(List* phead, ET val){
assert(phead != NULL);
if ((*phead) == NULL){
printf("表空，无法删除！\n");
return;
}
linkedListWithoutHeadNodeSortByValue(phead);
Node* p = *phead;
Node* q = *phead;
while (p != NULL){
if (p->next->data == val){
break;
}
p = p->next;
}
q = p->next;
while (q != NULL){
if (q->data != val){
break;
}
q = q->next;
}
p->next = q;
if (p->data == val){
linkedListWithoutHeadNodeDropHead(phead);
}
}