数据结构-单链表

单链表是一种链式存取的数据结构,用一组地址任意的存储单元存放线性表中的数据元素.
以结点来表示,每个结点是由元素 + 指针组成.
以结点的序列表示线性表称作线性链表(单链表),单链表是链式存取的结构.
单链表设头指针head指向开始结点

/**
 创建一个单链表
 */
typedef struct _Sample_List
{
    int Data;
    struct _Sample_List *next;
}Sample_List;

/**
 初始化一个头结点

 @return 返回一个链表
 */
Sample_List *Create_Link()
{
    Sample_List *head;
    head = (Sample_List *)malloc(sizeof(Sample_List));
    if (head == NULL) {
        perror("malloc:");
    }
    head->Data = 0;
    head->next = NULL;
    return head;
}

/**
 顺序插入一个节点

 @param head 头结点
 @param value 插入值
 @return 返回一个新链表
 */
int Inser_Link(Sample_List *head, int value)
{
    Sample_List *current = head;
    Sample_List *New;
    New = (Sample_List *)malloc(sizeof(Sample_List));//开辟空间
    if (New == NULL) {
        perror("malloc new");
    }
    New->Data = value;
    while ((current->next != NULL) && (value > current->next->Data)) {
        current = current->next;
    }
    if (current->next == NULL) {//查找到最后一个开始插入
        current->next = New;
        New->next = NULL;
    }else{
        New->next = current->next;//这个是中间插入,比较绕
        current->next = New;
    }
    
    return 0;
}

/**
 单链表的打印

 @param head 表头
 */
void sample_List_display(Sample_List *head)
{
    for (; head; head = head->next) {
        printf("%d", head->Data);
        printf("\n");
    }
}

int main(int argc, char * argv[]) {

    Sample_List d = {1000,0},c = {100, &d},b= {10, &c}, a = {1, &b};
    Inser_Link(&a, 20);
    Inser_Link(&a, 2000);
    sample_List_display(&a);
    return 0;
}

1
10
20
100
1000
2000

这里的顺序插入,一种是在最后插入,一种是在中间插入,在中间插入有点绕.我们用一个图片来说明

 

/**
 删除已有的节点

 @param head 头节点
 @param value 删除值
 @return 返回新链表
 */
int Delete_Note(Sample_List *head, int value)
{
    Sample_List *history = head;
    Sample_List *current = head->next;
    while ((current != NULL) && (current->Data != value)) {
        history = current;
        current = current->next;
    }
    if (current == NULL) {
        if (head->next == NULL) {
            printf("list is empty");
        }else{
            printf("not find this node");
        }
        return -1;
    }else{
        history->next = current->next;//删除替换指针
        free(current);
        printf("delete this node success");
    }
    return 0;
}

有关于删除链表需要替换掉对应指针

 

/**
 查找任意一个节点

 @param head 头节点
 @param key 查找值
 @return 返回 -1 失败  0 成功
 */
int Search_Link(Sample_List *head, int key)
{
    Sample_List *current = head->next;
    while ((current != NULL) && (current->Data) != key) {
        current = current->next;
    }
    if (current == NULL) {
        if (head->next == NULL) {
            printf("link is empty");
        }else{
            printf("not find");
        }
        return -1;
    }else{
        printf("find success!");
    }
    return 0;
}

/**
 链表逆序(逆置)

 @param head 头节点
 @return 返回新链表
 */
Sample_List *Reverse_Link(Sample_List *head)
{
    Sample_List *current,*record;
    if (head->next == NULL || head->next->next == NULL) {
        return head;
    }
    current  = head->next;
    head->next = NULL;
    while (current != NULL) {
        record = current->next;//这个地方比较绕
        current->next = head->next;//当前节点后驱前指
        head->next = current;//一直执行当前的点
        current = record;  //指针后移
    }
    return head;
}

/**
 遍历链表各个节点

 @param head 头节点
 */
void Print_Link(Sample_List *head)
{
    Sample_List *current = head->next;
    printf("各个节点:\n");
    while (current != NULL) {
        printf("%d->",current->Data);
        current = current->next;
    }
}

/**
 获取链表长度,多少个节点

 @param head 头节点
 @return 返回长度
 */
int Length_Link(Sample_List *head)
{
    Sample_List *current = head->next;
    int count = 0;
    while (current != NULL) {
        count++;
        current = current->next;
    }
    return count;
}

/**
 释放链表

 @param head 头节点
 */
void Free_Link(Sample_List *head)
{
    Sample_List *current = head->next;
    Sample_List *record = head;
    while (current != NULL) {
        record = current;
        current = current->next;
        free(record);
    }
    free(head);
    printf("free success");
    exit(0);
}

参考:https://blog.youkuaiyun.com/mr_chenping/article/details/8224141
        https://www.jianshu.com/p/9d017562bfb9