链表 创建 插入 删除 查找 合并

#define _CRT_SECURE_NO_DEPRECATE  /*取消scanf,printf不安全之类的错误提示*/
#include <stdio.h>
#include <stdlib.h>

typedef struct node
{
    int value;
    struct node* next;
}listnode;

listnode* Creat_List1(int nodenum, int *data); //最先进去的元素在最后面
listnode* Creat_List2(int nodenum, int *data); //最先进去的元素在最前面
int Get_Link_Element(listnode* head, int i); //取得头指针为head的链表中的第i个元素的值(包括第0个元素)
void Insert_List(listnode* head, int a, int i);
void Delet_List(listnode* head, int i); //删除第i个元素
listnode* Merge_TWO_Linklist(listnode *list1, listnode *list2);//合并两个有序链表

int main()
{
    int data;
    listnode *linka, *linkb, *linkc, *linkd, *linke;
    linka = (listnode*)malloc(sizeof(listnode));
    linkb = (listnode*)malloc(sizeof(listnode));
    linkc = (listnode*)malloc(sizeof(listnode));
    linkd = (listnode*)malloc(sizeof(listnode));
    linke = (listnode*)malloc(sizeof(listnode));
    int a[5] = { 1, 3, 5, 7, 9 };
    int b[3] = { 2,2, 4 };
    linka = Creat_List2(5, a);
    linkb = Creat_List2(3, b);
    Insert_List(linkb, 10, 1);
    Delet_List(linkb, 1);
    linkc=Merge_TWO_Linklist(linka, linkb);
    data = Get_Link_Element(linkb, 1);
    printf("%d\n", data);
}

//新元素总是插入到头指针后面，结果就是原先的元素一直往后移
listnode* Creat_List1(int nodenum,int *data)
{
    listnode *pc; //保存新节点
    listnode *head;
    head = (listnode*)malloc(sizeof(listnode));
    head->next = NULL; //先建立一个带头结点的单链表
    /*开始插入元素*/
    for (int i = 0; i < nodenum; i++)
    {
        pc = (listnode*)malloc(sizeof(listnode));
        pc->value = data[i];
        pc->next = head->next;
        head->next = pc;
    }
    return head;
}
//新元素插入到头指针后面，头指针一直往后移
listnode* Creat_List2(int nodenum, int *data)
{
    listnode *pc; //保存新节点
    listnode *head;
    listnode *r;//保存产生的链表
    head = (listnode*)malloc(sizeof(listnode));
    head->next = NULL; //先建立一个带头结点的单链表
    r = head;
    /*开始插入元素*/
    for (int i = 0; i < nodenum; i++)
    {
        pc = (listnode*)malloc(sizeof(listnode));
        pc->value = data[i];
        head->next = pc;
        pc->next = NULL;
        head = pc;
    }
    return r;
}

//取得头指针为head的链表中的第i个元素的值(包括第0个元素)
int Get_Link_Element(listnode* head, int i)
{
    /*创建一个扫描指针，让它指向第一个元素*/
    listnode* pc;
    int j = 0; //计数
    pc = (listnode*)malloc(sizeof(listnode));
    pc = head->next;
    while (pc != NULL && j < i) //遍历
    {
        pc = pc->next;
        j++;
    }
    if (pc == NULL || j > i) exit(-1);
    return pc->value;
}

/*
*合并两个有序链表,把list2合并到list1
*/
listnode* Merge_TWO_Linklist(listnode *list1, listnode *list2)
{
    listnode *pc1, *pc2, *pc3,*list3;
    pc1 = (listnode*)malloc(sizeof(listnode));
    pc2 = (listnode*)malloc(sizeof(listnode));
    pc3 = (listnode*)malloc(sizeof(listnode));


    pc1 = list1->next;
    pc2 = list2->next;
    pc3 = list1;
    list3 = pc3;
    while (pc1 != NULL && pc2 != NULL)
    {
        if (pc1->value <= pc2->value) {
            pc3->next = pc1;
            pc3 = pc3->next;
            pc1 = pc1->next;
        }
        else{
            pc3->next = pc2;
            pc3 = pc3->next;
            pc2 = pc2->next;
        }
    }
    if (pc1 == NULL) pc3->next = pc2;
    if (pc2 == NULL) pc3->next = pc1;
    free(list2);
    return list3;
}

void Insert_List(listnode* head, int a, int i)
{
    listnode *pc;
    listnode *s;
    pc = head->next;//令pc指向第一个元素
    int j = 1;
    while (pc != NULL && j < i)
    {
        pc = pc->next; //pc后移动
        j++;
    }
    if (pc == NULL)
    {
        printf("error\n");
        exit(-1);
    }

    s = (listnode*)malloc(sizeof(listnode));
    s->value = a;
    s->next = pc->next;
    pc->next = s;
}

//删除第i个元素
void Delet_List(listnode* head, int i)
{
    listnode *temp = NULL;
    int j = 1; //计数
    head = head->next;
    while (head != NULL && j < i)
    {
        head = head->next;
        j++;
    }
    if (head == NULL)
    {
        printf("error\n");
        exit(-1);
    }
    temp = head->next;
    head->next = temp->next;
    //head = head->next->next;
    free(temp);
}