【数据结构作业—02】双链表

2.实现下述要求的Locate运算的函数

问题描述

设有一个带表头结点的双向链表L，每个结点有4个数据成员：指向前驱结点的指针prior、指向后继结点的指针next、存放数据的成员data和访问频度freq。所有结点的freq初始时都为0。每当在链表上进行一次Locate (L, x)操作时，令元素值为x的结点的访问频度freq加1，并将该结点前移，链接到与它的访问频度相等的结点后面（如果该结点没有找到与它访问频度相等的结点，链接到表头后面结点），使得链表中所有结点，保持按访问频度递减的顺序排列，以使频繁访问的结点总是靠近表头。

解决方案要求

输入参数：

1. 输入n，n表示双向链表L的长度，L中的结点的data域依次为1到n。
2. 随机多次调用Locate函数，输入x（调用函数次数由用户决定）。

输出参数：

调用Locate函数结束后，从头结点开始依次输出链表L中个结点的内容（data+freq）。

参考样例：

代码：

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

typedef int ListData;
typedef struct DoubleNode {
    ListData data, frequency;
    struct DoubleNode *prior, *next;
}DoubleNode, *DoubleList;

void CreateDoubleList (DoubleList &first) {
    first = (DoubleNode*)malloc(sizeof(DoubleNode));
    if(first == NULL)    {
        cout << "存储分配错误！" << endl;
        exit(1);
    }
    first->prior = first->next = first;
}

void IniteList(DoubleList &first, ListData n)    {
    DoubleNode *carrier, *temp = first;
    for (int i = 0; i < n; i++)    {
        carrier = (DoubleNode*)malloc(sizeof(DoubleNode));
        carrier->data = i + 1;
        carrier->frequency = 0;
        //Insert
        carrier->prior = temp;
        temp->next = carrier;
        carrier->next = first;
        carrier->next->prior = carrier;
        
        temp = carrier;
    }
}

DoubleList Locate(DoubleList &first, ListData x, ListData n)    {
    DoubleNode *temp = first->next;
    while(temp->data != x && temp != first)    {
        temp = temp->next;
    }
    if (temp == first)    {
        cout << "Please input number range from " << 1 << " to " << n << endl;
        exit(1);
    }
    else
        return temp;
}

void SortList(DoubleList &first, ListData x, ListData n)    {
    DoubleNode *temp;
    temp = Locate(first, x, n);
    int tempNumber;
    temp->frequency++;
    if (temp->prior != first)    {
        while (temp->frequency > temp->prior->frequency)    {
            //SWAP 
            tempNumber = temp->prior->data;
            temp->prior->data = temp->data;
            temp->data = tempNumber;
            //cout << "temp->prior->data " << temp->prior->data << endl;
            //cout << "temp->data " << temp->data << endl;
            
            tempNumber = temp->prior->frequency;
            temp->prior->frequency = temp->frequency;
            temp->frequency = tempNumber;
            //cout << "temp->prior->frequency " << temp->prior->frequency << endl;
            //cout << "temp->frequency " << temp->frequency << endl;
        }
    }    
}

int main()    {
    int n;
    cout << "Please input the link list length:" << endl;
    cin >> n;
    
    cout << "The link list data are" << endl;
    for (int i = 0; i < n; i++)    
        cout << "The   " << i + 1 << " node is   " << i + 1 << ", its frequency is 0." << endl;
    
    cout << "Let's start to test Locate Function.(-1 meansstopping input number)" << endl;
    
    DoubleList first;
    CreateDoubleList(first);
    IniteList(first, n);
    
    int x = 0;
    while(1)    {
        cout << "Please input number :";
        cin >> x;
        if (x != -1) {
            SortList(first, x, n);
        } 
        else    break;
        
        
    }
    cout << "After test, the link list data are:" << endl;
    DoubleNode *temp = first->next;
    int count = 0;
    while(temp != first)    {
        count++;
        cout << "The   " << count << " node is   " << temp->data 
            << ", its frequency is " << temp->frequency << "." << endl;
        temp = temp->next;
    }
    
    return 0;
}