[小算法] 合并两有序链表

#include "stdafx.h"
#include <iostream>
#include <fstream>
using namespace std;

ifstream fin("data.txt");

struct Link
{
    int Data;
    Link *Next;
};

Link MergeLinks(Link *linka, Link *linkb);
void PrintLink(Link * head);

int _tmain(int argc, _TCHAR* argv[])
{
    Link linka, linkb, *pointera,*pointerb;
    linka.Data = 0, linkb.Data = 0, linka.Next = NULL, linkb.Next = NULL;
    pointera = &linka, pointerb = &linkb;
    Link *newNode;
    //build two links according the data.txt file
    while(true)
    {
        int data = 0;
        fin >> data;
        if(data != -1)
        {
            newNode = new Link();
            newNode->Data = data;
            newNode->Next = NULL;
            pointera->Next = newNode;
            pointera = pointera->Next;
        }
        else
        {
            break;
        }
    }
    cout << "Link A: ";
    PrintLink(&linka);
    cout << endl;
    while(true)
    {
        int data = 0;
        fin >> data;
        if(data != -1)
        {
            newNode = new Link();
            newNode->Data = data;
            newNode->Next = NULL;
            pointerb->Next = newNode;
            pointerb = pointerb->Next;
        }
        else
        {
            break;
        }
    }
    cout << "Link B: ";
    PrintLink(&linkb);
    cout << endl;

    Link *result = &MergeLinks(&linka, &linkb);
    PrintLink(result);
    cout << endl;
    system("pause");
    return 0;
}

//merge the two links, destory the original links
Link MergeLinks(Link *linka, Link *linkb)
{
    Link * pointera, * pointerb, *temp;
    pointera = linka;
    pointerb = linkb;

    while(pointera->Next != NULL && pointerb->Next != NULL)
    {
        if(pointera->Next->Data > pointerb->Next->Data)
        {
            temp = pointera->Next;
            pointera->Next = pointerb->Next;
            pointerb->Next = pointerb->Next->Next;
            pointera->Next->Next = temp;
        }
        else
        {
            pointera = pointera->Next;
        }
    }

    if(pointerb->Next != NULL)
    {
        pointera->Next = pointerb ->Next;
    }

    return *linka;
}

void PrintLink(Link * head)
{
    Link *pointer = head->Next;
    while(pointer != NULL)
    {
        cout << pointer->Data << " ";
        pointer = pointer->Next;
    }
}

 

 

data.txt内容如下：

1 3 6 8 10 50 215 -1

2 4 6 7 9 12 123 216 217 225 226 -1