数据结构之线性表的链式表示和实现

//测试环境:VS2015

#include "stdafx.h"
#include<stdlib.h>
#include<stdio.h>

//宏定义
#define ERROR 0
#define OK 1
//定义单链表的存储结构

typedef struct LNode
{
    int data;
    struct LNode *next;
}LNode, *LinkList;

//在带头节点的链表中获取第i个节点值，并用元素e返回
int getElem(LinkList L, int i, int &e)
{
    //L是带头节点的单链表的头指针
    LinkList p = L->next;
    int j = 1;
    while (p&&j < i)
    {
        p = p->next;//寻找第i个节点
        j++;
    }
    if (!p || j > i)
    {
        return ERROR;
    }
    e = p->data;
    return OK;
}

//在带头节点的链表中的第i个节点前插入元素e
int listInsert(LinkList &L, int i, int e)
{
    LinkList p = L;
    int j = 0;
    while (p&&j < i-1)
    {
        p = p->next;//寻找第i-1个节点
        j++;
    }
    if (!p||j>i-1)
    {
        return ERROR;
    }
    LinkList s = (LinkList)malloc(sizeof(LNode));
    if (!s)
    {
        return ERROR;
    }
    s->data = e;
    s->next = p->next;
    p->next = s;
    return OK;
}

//在头节点的单链表L中，删除第i个节点的元素，并用e返回
int listDelete(LinkList &L, int i, int &e)
{
    LinkList p = L;
    int j = 0;
    while (p->next&&j < i - 1)
    {
        p = p->next;//寻找第i-1个节点
        j++;
    }
    if (!(p->next) || j > i - 1)
    {
        return ERROR;
    }
    LinkList q = p->next;
    e = q->data; 
    p->next = q->next;
    free(q);
    return OK;
}

//创建链表
int createList(LinkList &L, int n)
{
    //按顺位序输入n个元素的值，建立带头节点的单链表
    L = (LinkList)malloc(sizeof(LNode));
    L->next = NULL;//建立头节点
    LinkList q = L;
    for (int i = 1; i <= n; i++)
    {
        LinkList s = (LinkList)malloc(sizeof(LNode));
        if (!s)
        {
            return ERROR;
        }
        scanf_s("%d", &s->data);
        q->next = s;
        s->next = NULL;
        q = s;
        //按逆序位输入
        //s->next = L->next;//连接第一个节点
        //L->next = s;
    }
    return OK;
}

//合并链表
int mergerList(LinkList &La, LinkList &Lb, LinkList &Lc)
{
    //已知单链表La,Lb按值非递减排列，合并后得到的单链表Lc也按值非递减排列
    LinkList pa = La->next;
    LinkList pb = Lb->next;
    LinkList pc = Lc = 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;
    free(Lb);//释放Lb的头节点
    return OK;
}

//测试
int main()
{
    int e;
    LinkList list1,list2,list3;
    //创建链表list1
    createList(list1, 7);
    for (int i = 1; i <= 7; i++)
    {
        getElem(list1, i, e);
        printf("%d ", e);
    }
    printf("\n");

    //插入节点
    listInsert(list1, 8, 100);
    for (int i = 1; i <= 8; i++)
    {
        getElem(list1, i, e);
        printf("%d ", e);
    }
    printf("\n");
    listDelete(list1, 1, e);
    for (int i = 1; i <= 7; i++)
    {
        getElem(list1, i, e);
        printf("%d ", e);
    }
    printf("\n");

    //创建链表list2
    createList(list2, 7);
    for (int i = 1; i <= 7; i++)
    {
        getElem(list2, i, e);
        printf("%d ", e);
    }
    printf("\n");

    //合并链表到list3
    mergerList(list1, list2, list3);
    for (int i = 1; i <= 14; i++)
    {
        getElem(list3, i,e);
        printf("%d ", e);
    }
    printf("\n");
    return 0;
}