40w随机数据找出其中次数出现最多的那个数(类似于在10亿百度ip中找出访问次数最多的那个ip)

来源：互联网发布：比尔盖茨书单知乎编辑：程序博客网时间：2024/06/14 00:37

其实这个问题本身是寻找Top ip,但是找不到那么多的ip,我用excl自己做了一个40w随机数所以改成在40w中寻找出现次数最多的那个数和出现的次数

#include <iostream>#include <stdio.h>#include <string>#include <map>#include <time.h>#define N 1000using namespace std;template<class T>class list;template<class T>class hashtable;//节点类template<class T>class  node{friend class list<T>;friend class hashtable<T>;template<class T1>friend ostream& operator <<(ostream& out,node<T1>  tmp);template<class T2>friend ostream&  operator <<(ostream& out,list<T2> l1);public:node(T _value){      value=_value;      next=NULL;}bool operator ==(node<T> *  tmp){return this->value==tmp->value;}private:T value;node<T>* next;};template<class T>ostream& operator <<(ostream& out,node<T>  tmp){ out<<tmp.value; return out;}//链表类template<class T>class  list{template<class T1>friend ostream&  operator <<(ostream& out,list<T1> l1);public:  /*========================================  *函数名:list  *函数参数: tmp head节点的初始值  *函数作用:构造函数  ===========================================*/list(node<T> * tmp=NULL){head=tmp;curr=NULL;}/*========================================  *函数名:push_back  *函数参数: newnode 插入节点  *函数作用:在链表中插入值  ===========================================*/void  push_back(node<T> * newnode){        if(head==NULL)        {        head=newnode;        curr=head;        }        else        {        curr->next=newnode;        curr=newnode;        }        newnode=NULL;}  /*========================================  *函数名:list_delete  *函数参数: value 删除的值  *函数作用:删除在链表中所有值为value  ===========================================*/void  list_delete(T value){      node<T>* tmp = head;      curr = head->next;      if (head->value == value)      {         head = curr;         delete tmp;         tmp = NULL;      }      else      {         while (curr != NULL)         {            if (curr->value == value)            {               tmp->next = curr->next;              delete curr;              curr = NULL;            }             else            {               tmp = curr;            }            curr = curr->next;         }      }}  /*========================================  *函数名:list_exists  *函数参数: tmp 查询的节点  *函数作用:查询某个节点在list中是否存在  ===========================================*/bool list_exists(node<T> *tmp){     bool isexists=false; if(tmp==NULL) { isexists=false; } if(tmp!=NULL) {            node<T>* t1=head;            while(t1!=NULL)            {            if(t1->value==tmp->value)            {            isexists=true;            break;            }            t1=t1->next;            } } return isexists;}  /*========================================  *函数名:getValue  *函数参数: index 需要获取的值的位置  *函数作用:获取对应位置的值  ===========================================*/   const  T  getValue(int index)        {           int i = 0;           string ptr = "-100";           node<T>* tmp = NULL;            tmp = head;           while (i != index)           {              if (tmp == NULL)              {                 return ptr;              }              tmp = tmp->next;              i++;           }             if (tmp != NULL)           {              return tmp->value;           }           else           {             return ptr;           }        }private:   node<T> *head;   node<T> *curr;};template<class T>ostream&  operator <<(ostream& out,list<T> l1){    node<T> * t=l1.head;    while(t!=NULL)    {    out<<*t<<'\t';    t=t->next;    }    return out;}//hash表类template<class T>class hashtable{public:    typedef int (*hash)(T value);  /*========================================  *函数名:hashtable  *函数参数: _fptr hash函数  *函数作用:构造函数  ===========================================*/  hashtable(hash _fptr){int i;for(i=0;i<N;i++){table[i]=NULL;}fptr=_fptr;}  /*========================================  *函数名:hash_insert  *函数参数: value 插入的值  *函数作用:在hash表中插入值  ===========================================*/ void  hash_insert(T value){      int key=fptr(value);        node<T> *newnode= new node<T>(value);      if(table[key]==NULL)      {           table[key]=newnode;              }       list[key].push_back(newnode);     }  /*========================================  *函数名:hash_find  *函数参数: value 查找的值  *函数作用:在hash表中查找值  ===========================================*/ bool hash_find(T value){   bool isfind=false;       int key=fptr(value);                     if(table[key]==NULL)       {          isfind=false;       }       else       {        node<T> *tmp=new node<T>(value);        isfind=list[key].list_exists(tmp);       }       return isfind;}  /*========================================  *函数名:hash_isempty  *函数参数: i 查询的key在hashtable 中  *函数作用:判断hash表中对应的key值是否空  ===========================================*/   bool hash_isempty(int i) { if (table[i] == NULL) return true; return false; }  /*========================================  *函数名:hash_lead_in  *函数参数: filename[]是文件名 index key值  *函数作用:把对应的key中链表导入文件中  ===========================================*/  void hash_lead_in(char filename[],int index){ FILE* rfp; char buf[20] = {'\0'}; rfp = fopen(filename,"wt+"); int i = 0; while (strcmp(list[index].getValue(i).c_str(),"-100") != 0) {    bzero(buf,sizeof(buf));    strcpy(buf,list[index].getValue(i).c_str());    fwrite(buf,sizeof(char),strlen(buf),rfp);    i++; } fclose(rfp);}private:node<T> * table[N];hash fptr;list<T> list[N];};//外置hash函数int hash_fun(string value){    int sum=0;    int i;    for(i=0;i<value.length();i++)    {       sum+=value[i];    }    return sum%N;}  /*========================================  *函数名:DownloadDataToHash  *函数参数: filename[]是文件名 hash1 hash表  *函数作用:把大文件中数据导入hash中  ===========================================*/  void DownloadDataToHash(char filename[],hashtable<string>& hash1){    FILE* rfp;    rfp = fopen(filename,"r+");    if (rfp == NULL)    {    perror("open:");    exit(-1);    }       char buf[1024];    char *find;     bzero(buf,sizeof(buf));    while (fgets(buf,1024,rfp))    {          //  find = strchr(buf,'\n');     //  if (find)     //  {    // *find = '\0';     //  }     hash1.hash_insert(buf);     bzero(buf,sizeof(buf));    }    fclose(rfp);}  /*=======================================================  *函数名:DealData  *函数参数: pstr[]存放所有值的下标 hash1 hash表  *函数作用:处理hash表中的每个key 值对应的链表并导入小文件中  =========================================================*/ void DealData(int pstr[],hashtable<string>& hash1){   int i;   int index = 0;   char filename[10] = {'\0'};   i = 288;   for (i = 0;i < N;i++)   {    if (!hash1.hash_isempty(i))    {      //记录下i方便后面读取查找        pstr[index] = i;        index++;        sprintf(filename,"a%d.dat",i);        hash1.hash_lead_in(filename,i);    }   }   }  /*=======================================================  *函数名:findMaxCount  *函数参数: filename文件名 savestring 保存出现次数最多的数据  *函数作用:处理每个小文件找出出现次数最多的数据  =========================================================*/ int findMaxCount(char filename[],char savestring[]){    FILE* rfp;    rfp = fopen(filename,"r+");    if (rfp == NULL)    {      perror("open:");      exit(-1);    }    map<string,int> map1;    char buf[1024];    char *find;    bzero(buf,sizeof(buf));    while (fgets(buf,1024,rfp))    {           find = strchr(buf,'\n');      if (find)      {      *find = '\0';      }     if (map1.find(buf) == map1.end())//map容器中没有该元素     {       map1[buf] = 1;     }     else     {       map1[buf] = map1[buf] + 1;     }     bzero(buf,sizeof(buf));    }     fclose(rfp);     map<int,string> map_sort;     map<string,int>::iterator it;     for (it = map1.begin();it != map1.end();it++)     {       map_sort[it->second] = it->first;     }     map<int,string>::iterator point;     point = map_sort.end();     --point;     bzero(savestring,sizeof(savestring));     strcpy(savestring,(point->second).c_str());     return point->first;}int main(int argc, char const *argv[]){  int pstr[N] = {0};//初始化    char filename[20] = {'\0'};    char savestring[20] = {'\0'};    char maxstring[20] = {'\0'};    int maxcount = 0;    int savecount = 0;  clock_t start = clock();//起始时间    hashtable<string> hash1(hash_fun);    DownloadDataToHash("40w随机数据.txt",hash1);    DealData(pstr,hash1);    int i = 0;    for (i = 0; i < N; i++)    {      if (pstr[i] == 0)      {        break;      }      sprintf(filename,"a%d.dat",pstr[i]);      savecount = findMaxCount(filename,savestring);      if (maxcount <= savecount)      {         bzero(maxstring,sizeof(maxstring));         strcpy(maxstring,savestring);         maxcount = savecount;      }      bzero(filename,sizeof(filename));    }    cout<<"出现次数最多的数:"<<maxstring<<endl;    cout<<"出现次数:"<<maxcount<<endl;    clock_t end = clock();//结束时间    double cost_time = (double)((end-start)/1000);    cout<<"程序用时为:"<<showpoint<<cost_time/1000<<"秒"<<endl;    system("rm -f *.dat");  return 0;}

运行结果和时间

0 0