Data_Struct(LinkList)

　　最近在学数据结构，学到链表这节作业有链表，毕竟菜鸟代码基本照看书上算法写的，再加上自己的小修改，这里先记录下来，万一哪天想看了，来看看。

　　里面有用到二级指针，还是不太理解，还有就是注释不多，后续有了更好的理解，再来添加

#define TRUE                    1
#define FALSE                    0
#define OK                    1
#define ERROR                    0
#define OVERFLOW                    -2
#define INFEASIBLE                    -1
#define Status                    int
#define ElemType                int

typedef struct LNode
{
    ElemType data;
    struct LNode *next;
}LNode;

typedef LNode LinkList;
Status ListInsert_L(LinkList L, int i, ElemType e);//插入函数
Status ListDelete_L(LinkList L, int i, ElemType *e);//删除某个元素
void CreateList_L(LinkList L, int n);//创建一个带头结点的空链表
void MergeList_L(LinkList *La, LinkList *Lb, LinkList **Lc);   //合并两个有序链表         

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


//新建带头结点的空链表
void CreateList_L(LinkList **L, int n)
{
    int i; LinkList *p = NULL;
    (*L) = (LinkList*) malloc (sizeof (LNode));
    (*L) ->next = NULL;
    printf("请输入链表元素 :\n");
    for(i = n; i > 0; --i)
    {
        p = (LinkList*) malloc (sizeof (LNode));//生成新结点
        scanf("%d", &p -> data);//输入元素值
        p -> next = (*L) -> next;
        (*L) -> next = p;//插入到表头
    }
}


//插入元素
Status ListInsert_L(LinkList *L, int i, ElemType e)
{
    LinkList *p = L;
    LinkList *s = NULL;
    int j = 0;
    while (p->next && j < i - 1)
    {
        p = p -> next;
        ++ j;
    }
    if(!p || j != i - 1)
    return ERROR;
    s = (LinkList*) malloc (sizeof(LNode));
    s -> data = e;
    s -> next = p ->next;
    p -> next = s;
    return OK;
}


//删除元素
Status ListDelete_L(LinkList *L, int i, ElemType *e)
{
    LinkList *p = L;
    LinkList *q;
    int j = 0;
    while(p -> next && j < i - 1)
    {
        p = p -> next;
        ++ j;
    }
    if(!(p -> next) || j > i - 1)
        return ERROR;
    q = p -> next;
    p -> next = q -> next;
    *e= q -> data;
    free(q);
    return OK;
}




void MergeList_L(LinkList *La, LinkList *Lb, LinkList **Lc)
{
    LinkList *pa = La -> next;
    LinkList *pb = Lb -> next;
    LinkList *pc = NULL;
    (*Lc) = pc =  La;
    while(pa && pb)
    {
        if(pa -> data <= pb -> data)
        {
            pc -> next = pa;
            pc = pa;
            pa = pa ->next;
        }
        else
        {
            pc -> next = pb;
            pc = pb;
            pb = pb -> next;
        }
    }
        pc -> next = pa ? pa : pb;//插入剩余段
        free(Lb);//释放Lb头结点
        Lb = NULL;

}


void Free(LinkList *L)
{
    if(L && L -> next)
         Free( L -> next);
    free(L);
    return;
}


int main()
{
        int selectn,length0,length1,location,e,counti;
        LNode *L1 = NULL,*L2 = NULL, *L3 = NULL, *la = NULL, *lc = NULL;
        printf("请输入新链表长度 ：\n");
        scanf("%d", &length0);
        CreateList_L(&L1, length0);
        printf("请选择 : \n");
        printf("1 : 插入元素\n");
        printf("2 : 删除元素\n");
        printf("3 : 合并链表\n");
        scanf("%d", &selectn);
        switch (selectn)
        {
        case 1 :
            printf("请输入插入位置 ：\n");
            scanf("%d", &location);
            printf("请输入要插入元素 ：\n");
            scanf("%d", &e);
            if(ListInsert_L(L1, location, e) == OK )
                {   //逆序输出
                    counti = 1;
                    la = L1;
                    printf("新链表的顺序为 ：\n");
                    while(la -> next)
                    {
                        la = la->next;
                        if(counti++ % 10)
                            printf("%-5d",la -> data);
                        else
                            printf("%-5d\n",la -> data);
                    }
                }
            else
                printf("插入异常\n");
                printf("\n");
            break;
        case 2 :
            printf("请输入要删除的位置 :\n");
            scanf("%d",&location);
            if(ListDelete_L(L1, location, &e) == OK)
            {
                printf("删除成功\n被删除元素为 : %-5d\n", e);
            }
            else
                printf("删除异常\n");
            break;
        case 3 :
            printf("请输入链表2 :\n");
            printf("请输入链表长度 :\n");
            scanf("%d", &length1);
            CreateList_L(&L2, length1);
            MergeList_L(L1, L2, &L3);
            L2 = NULL;
            lc = L3 -> next;
            printf("新链表顺序为 :\n");
            counti = 1;
            while(lc)
            {    if(counti++ % 10)
                    printf("%-5d", lc -> data);
                else
                    printf("%-5d", lc -> data);
                lc = lc -> next;
            }
            printf("\n");
            break;
        default :
            printf("ERROR\n");
            break;
        }
        Free(L1);
        L1    = NULL;
        L3    = NULL;
        system("pause");
        return 0;
}