笔试题之 ip 快速查找

笔试题之去哪：ip快速查找

个人信息：就读于燕大本科软件工程专业 目前大三;

本人博客：google搜索“cqs_2012”即可;

个人爱好：酷爱数据结构和算法，希望将来搞科研为人民作出自己的贡献;

博客内容：笔试题之去哪：ip快速查找;

博客时间：2014-3-29

编程语言：C++

编程坏境：Windows

编程工具：vs2008

 

• 引言

突然发现去哪的笔试题很有共性，好像每一次笔试题，都有一个大型数据文件，然后让根据大型文件计算或者查找某个关键字。这种考题个人感觉回落在折半查找，哈希，trie树上等等。

• 题目

  • 9月24日，去哪儿网2014校招西安站笔试题
    给定一个200MB的文本文件，里面存的是IP地址到真实地址信息的映射信息，例如：211.200.101.100北京
    然后给你6亿个IP地址，请设计算法快速的打印出所对应的真实地址信息。

• 思路

个人感觉此题从大方向上会用到tire树，接着从trie树每个节点上会用到折半查找。个人设计数据结构如下

个人整体思路是

1.将文本信息读到内存中，每读一条ip信息就插入到trie tree中，在插入过程中，会遇到查找操作，这时候选择折半查找就好;

2.整个trie tree的高度都是3;

3.整个trie tree是一颗高度平衡树，即每个叶子到根节点的长度都是4;

4.整个算法会有好多棵这样的树，每一个ip的前三位数字会作为一棵树的根，如果已经包含这样根的树，直接插入就好，否则建立新树;

 

• 实验

实验有两部分：

1.随机生成一个文本信息 ip个数 1000,000;

2.读取文本，然后插入trie tree 中;

3.输入关键字;

4.在trie trees中进行查询;

5.返回结果;

6.每一步程序执行之后，都是耗时显示;

7.建立文本速度还行，建立trie trees 耗时很长,查询非常快，快的不得了;

程序结果截图如下

文本说明 20m，为什么不用200m，还有一些问题，稍后解决给出问题，致bad alloc问题，请谅解，谢谢。

• 代码

mine_string.h

#include <iostream>#include <string>#include <limits>using namespace std;// extra the class of stringclass String:public string{public:// function 1: mode the add of int( (-3) + (-3) ) = - 6// input: 两个字符串 a 和 b，里面放的都是整数;// output: 返回一个字符串，字符串里面是整数;// 功能: 实现参数两个整数的相加操作，结果存在返回的字符串里static string ADD_Int(string a,string b);// function 2: make a-b mode int a - b; 7 - (-3) = 10// input: 两个字符串 a 和 b，里面放的都是整数;// output: 返回一个字符串，字符串里面是整数;// 功能: 实现参数两个整数的相减操作，结果存在返回的字符串里static string MINUS_Int(string a,string b);// function 3: make a*b mode int a * b;// input: 两个字符串 a 和 b，里面放的都是整数;// output: 返回一个字符串，字符串里面是整数;// 功能: 实现参数两个整数的相乘操作，结果存在返回的字符串里static string MULT_Int(string a,string b);// function 4: mode the division a/b// input: 两个字符串 a 和 b，里面放的都是整数;// output: 返回一个字符串，字符串里面是整数;// 功能: 实现参数两个整数的相除操作，结果存在返回的字符串里static string DIV_Int(string a,string b);// function 5: pow number a^b// input: 两个字符串 a 和 b，里面放的都是整数;// output: 返回一个字符串，字符串里面是整数;// 功能: 实现参数两个整数的a^b操作，结果存在返回的字符串里static string Pow_Int(string a,string b);// function 6: int To string :"123" = 123// input: 一个int数 a;// output: 返回一个字符串，字符串里面是整数;// 功能: 将整数a转换成对应的字符串格式static string Int_To_String(int x);// function 7: static char division a/b : 4 / 3static string Division(string a,string b);// function 8: make a-b mode int a - b; 4 - 3static string MinusInt(string a,string b);// function 9: mode the add of int :3 + 4static string AddInt(string a,string b);// function 10: make char to the int number :'9' = 9static int CharToNumber(char c);// function 11: make int to the model char : 7 = '7'static string IntToChar(int i);// function 12: check whether the string is legal static bool check_all_number(string a);// function 13: compare string a and b// input: 两个字符串 a 和 b，里面放的都是整数;// output: 返回一个字符，字符里是a和b的大小关系;// 功能: 实现参数两个整数的a和b比较操作，结果< or = or >存在返回的字符里static char Compare(string a,string b);// function 14: make string into standard string numberstatic bool Standardization(string &a);// function 15: make string(>0) into standard int number// input: 一个字符串 a，里面放的是一个整数;// output: 返回一个字符串，字符串里是a对应的整形数据;// 功能: 将存在字符串里的整数取出来，放在整形容器里，然后返回，根据返回的结果可以判定是否转换成功static std::pair<bool,int> String_into_intNumber(string &a);};// mode the add of intstring String::ADD_Int(string a,string b){// exception of inputif( a.empty() )return b;else if( b.empty() )return "0";if(!check_all_number(a) || !check_all_number(b)){return "exception of input ADD_Int";}Standardization(a);Standardization(b);if(a[0] != '-' && b[0] != '-')return AddInt(a,b);else if(a[0] != '-'&& b[0] == '-')return MinusInt( a,b.substr( 1,b.size() ) );else if(a[0] == '-'&& b[0] != '-')return MinusInt(b,a.substr(1,a.size()));else return '-'+AddInt(a.substr(1,a.size()),b.substr( 1,b.size() ));};// make a-b mode int a - b;string String::MINUS_Int(string a,string b){// exception of inputif( a.empty() )return b;else if( b.empty() )return "0";if(!check_all_number(a) || !check_all_number(b)){return "exception of input Multiplies_Int";}Standardization(a);Standardization(b);if(a[0] != '-' && b[0] != '-')return MinusInt(a,b);else if(a[0] != '-' && b[0] == '-')return AddInt(a,b.substr(1,b.size()));else if(a[0] == '-' && b[0] != '-')return "-"+AddInt(a.substr(1,a.size()),b);else return MinusInt( b.substr(1,b.size()) , a.substr(1,a.size()) );};// make a*b mode int a * b;string String::MULT_Int(string a,string b){// exception of inputif( a.empty() )return b;else if( b.empty() )return "0";if(!check_all_number(a) || !check_all_number(b)){return "exception of input Multiplies_Int";}Standardization(a);Standardization(b);string::size_type i = a.size(),j = b.size();string c = "0",d = "";bool fushu = (a[0] == '-' && b[0] != '-')||(a[0] != '-' && b[0] == '-');if(a[0] == '-')a = a.substr(1,a.size());if(b[0] == '-')b = b.substr(1,b.size());int jinwei = 0;for( j = b.size()-1 ; j < b.size() ;j--){// each number of b to * a jinwei = 0;for( i = a.size()-1 ; i < a.size() ;i-- ){d = IntToChar(   ( CharToNumber(a[i]) * CharToNumber(b[j]) + jinwei ) % 10 )+ d ;jinwei = ( CharToNumber(a[i]) * CharToNumber(b[j]) + jinwei ) / 10 ;}if(jinwei)d = IntToChar(jinwei) +d;// add all number resultc = ADD_Int(c,d);d = "";unsigned int zero = 0 ;while( zero < b.size() - j ){d = d + '0';zero ++;}}Standardization(c);if( fushu && c != "0" )return '-'+c;else return c;};// mode the division a/bstring String::DIV_Int(string a,string b){// exception of inputif( a.empty() )return "0";else if( b.empty() )return "e";if(!check_all_number(a) || !check_all_number(b)){return "exception of input DIV_Int";}Standardization(a);Standardization(b);if(b == "0")return "e";bool fushu =  (a[0] == '-' && b[0] != '-')||(a[0] != '-' && b[0] == '-');if( a[0] == '-' )a = a.substr(1,a.size());if( b[0] == '-' )b = b.substr(1,b.size());if( Compare(a,b) == '<' )return "0";string yushu = "";string beichushu = a.substr(0,b.size());string shang = Division( beichushu , b);yushu =  MinusInt( beichushu ,MULT_Int( shang, b) );string c = shang;for(string::size_type i = b.size(); i<a.size(); i++){beichushu =   yushu+ a[i]     ;shang = Division( beichushu , b);c = c + shang;yushu =  MinusInt( beichushu ,MULT_Int( shang, b) );}Standardization(c);return fushu?('-'+c):c;};// function: pow number x,ystring String::Pow_Int(string a,string b){// exception of inputif( a.empty() )return "0";else if( b.empty() )return "e";if(!check_all_number(a) || !check_all_number(b)){return "exception of input DIV_Int";}Standardization(a);Standardization(b);string result = "1" ;if(Compare(b,"0") != '<')for(string i ="0" ;Compare(i,b) == '<' ;i = AddInt(i,"1")){result = MULT_Int(result,a);}else for(string i ="0" ;Compare(i,b) == '>' ;i = MINUS_Int(i,"1")){result = DIV_Int(result,a);}return result ;};// function : int To string string String::Int_To_String(int x){bool fushu = false;string result="";if(x < 0 ){fushu = true ;x = -x;}else if( x == 0 )return "0";while(x){result = IntToChar(x % 10) + result;x = x/10;}if(fushu)result = "-"+result;return result;};// static char division a/bstring String::Division(string a,string b){// exception of inputif( a.empty() )return "0";else if( b.empty() )return "e";if(!check_all_number(a) || !check_all_number(b)){cout<<"exception of input Division"<<endl;return "e";}Standardization(a);Standardization(b);int i = 0;while( i<=9 ){// if a - b*i < bif(  Compare(   MINUS_Int(   a  ,   MULT_Int(IntToChar(i),b)    ) , b ) == '<'    )break;i++;}if( i>9 )return "e";return ""+IntToChar(i);};// make a-b mode int a - b;string String::MinusInt(string a,string b){// exception of inputif(!check_all_number(a) || !check_all_number(b))return "exception of input MinusInt";Standardization(a);Standardization(b);// particular string of inputif(a.empty()){if(b.empty())return "0";elsereturn "-"+b;}else if(b.empty()){return a;}// normal number a < bstring c = "";bool check = true ;if(Compare(a,b) == '=')return "0";else if(Compare(a,b) == '<'){c = a ;a = b ;b = c ;c = "";check = false ;}// normal number a >= bstring::size_type i = a.size()-1, j = b.size()-1;int jiewei = 0,now;while(i < a.size() && j < b.size()){now = CharToNumber(a[i]) - CharToNumber(b[j]) - jiewei ;if( now < 0 ){jiewei = 1;now = 10 + now ;}else jiewei = 0;c = IntToChar(now)  + c ;i--;j--;}while(i < a.size()){now = CharToNumber(a[i]) - jiewei ;if( now < 0 ){jiewei = 1;now = 10 + now ;}else jiewei = 0;c = IntToChar( now )  + c ;i--;}Standardization(c);if(!check)c = '-' + c;return c; };// mode the add of intstring String::AddInt(string a,string b){// exception of inputif( a.empty() )return b;else if( b.empty() )return "0";if(!check_all_number(a) || !check_all_number(b)){return "exception of input AddInt";}Standardization(a);Standardization(b);string::size_type i = a.size()-1 ,j = b.size()-1 , k = 0 ;string c = "";int jinwei = 0;while( i < a.size() && j < b.size() ){c = IntToChar( ( CharToNumber(a[i]) + CharToNumber(b[j]) + jinwei ) % 10 ) + c;jinwei = ( CharToNumber(a[i]) + CharToNumber(b[j]) + jinwei ) / 10;j--;i--;}while( j < b.size()  ){c =  IntToChar( ( CharToNumber(b[j]) + jinwei ) % 10 ) + c;jinwei = ( jinwei + CharToNumber(b[j]) ) / 10;j--;}while( i < a.size() ){c =  IntToChar( ( CharToNumber(a[i]) + jinwei ) % 10 ) + c;jinwei = ( jinwei + CharToNumber(a[i]) ) / 10;i--;}if( jinwei )c = IntToChar(  jinwei  ) + c;Standardization(c);return c;};// make char to the int numberint String::CharToNumber(char c){if( c >= '0' && c <= '9' )return int(c - '0');else {cout<<c<<" exception of input CharToNumber "<<endl;system("pause");return 0;}};// make int to the model charstring String::IntToChar(int i){if( i >= 0 && i <= 9 ){string c = "";return c+char(i+48);}else{cout<<i<<" exception of input IntToChar"<<endl;system("pause");return "e";}};// check whether the string is legal bool String::check_all_number(string a){if(a.empty())return true ;string::size_type L = a.size(),i = 0;if(a[0] == '-')i++;while( i < L ){if( a[i] < '0' || a[i] > '9')return false;i++; }return true ;};// compare string a and bchar String::Compare(string a,string b){if(a.empty() || b.empty()){cout<<"error of input compare";return 'e';}else{if(!check_all_number(a) || !check_all_number(b)){return 'e';}Standardization(a);Standardization(b);if(a[0] == '-' && b[0] != '-')return '<';else if( a[0] != '-' && b[0] == '-')return '>';bool fushu = (a[0] == '-');if(a.size() > b.size() )return fushu?'<':'>';else if(a.size() == b.size()){for(string::size_type i = 0;i < a.size(); i++){if(a[i] > b[i])return fushu?'<':'>';if(a[i] < b[i])return fushu?'>':'<';}return '=';}return fushu?'>':'<';}};// make string into standard string numberbool String::Standardization(string &a){if(!check_all_number(a)){cout<<a<<" exception of input Standardization"<<endl;return false;}string::size_type i = 0;bool fushu = false ;if( a[0] == '-' ){fushu = true;i = 1;}while(i < a.size()){if(a[i] != '0')break;i++;}if(i == a.size())i--;a = a.substr(i,a.size());if( fushu && a != "0")a = '-' + a;return true ;};// make string(>0) into standard int numberstd::pair<bool,int> String::String_into_intNumber(string &a){if(Standardization(a)){//int max_int = numeric_limits<int>::max()-1 ;//string max = Int_To_String(max_int);bool fushu = false;if(a[0] == '-'){fushu = true ;a = a.substr(1,a.length());}//if(Compare(a,max) != '<')//{//cout<<"溢出 exception"<<endl;//return std::make_pair(false,0);//}int result = 0 ;for(size_t i =0;i<a.length();i++){result = result * 10 + CharToNumber(a[i]);}if(fushu)result = - result;return std::make_pair(true,result);}else{cout<<"exception of function String_into_intNumber input"<<endl;return std::make_pair(false,0);}};

test.cpp

// include head file#include<fstream>#include<vector>#include<iterator>#include<Windows.h>#include<utility>#include"mine_string.h"// myclassclass trie_leaf{public:int key;string place;trie_leaf(){key = -1;place = "NULL";}};class trie_node{public:int key;vector<trie_node*>  *child ;vector<trie_leaf*>  *leaf ;trie_node(){key = -1 ;child = NULL ;leaf = NULL ;}};// function: make file// input: a size_t number,standing ip ziduan number// output: a file（"ip.txt"）, which including all the ip data// 功能: 随机生成一个file（"ip.txt"），里面存储模拟生成的ip地址void _Make_ip_file(size_t size);// function: read data;// input: a file（"ip.txt"）, which including all the ip data;// output: a trie tree root point// 功能: 将文件数据读到内存中，存在好多个 trie trees 中vector<trie_node*>* ip_data_read();// function: binary_search// input: a trie node and ip keyword// output: the pair<bool,int>,if bool true, and find keyword; or not find = false// 功能: 在指定节点中，查找关键字,若能找到返回<true,下标>;否则返回<false,应该插入的下标>std::pair<bool,int> binary_search(vector<trie_node*> *tree,int key);// function: binary_search leaf// input: a trie leaf and ip keyword// output: the pair<bool,int>,if bool true, and find keyword; or not find = false// 功能: 在指定叶子中，查找关键字,若能找到返回<true,下标>;否则返回<false,应该插入的下标>std::pair<bool,int> binary_search_leaf(vector<trie_leaf*> *tree,int key);// function: insert keyword into trie tree// input: a trie node and ip information// output: void// 功能：将 ip 信息插入到当前 trie 节点中void insert_into_trie(vector<trie_node*> *tree,int *data,int length,string place);// function: _Trie_tree_visit// input:a trie tree' root point// output:void// 功能: 遍历 trie 树void _Trie_tree_visit(vector<trie_node*> *tree,int level);// function: _Trie_tree_visit// input:a trie tree' root point// output:void// 功能: 遍历 trie 树的叶子void _Trie_tree_visit_leaf(vector<trie_leaf*> *tree,int level);// function: ip binary search// input: a trie tree and a keyword key// output: return pair<bool,string>// 功能：折半查找ip，返回其信息std::pair<bool,string> _Ip_binary_search(vector<trie_node*>* tree,string key);// function: delete the space we used;// input: a trie tree root point vector point, and level// output: void// 功能: 释放掉我们开辟的空间，节省空间资源void _delete_trie_tree(vector<trie_node*>* tree,int level);// function: mainint main(){DWORD s,e;string ip ;std::pair<bool,string> r;vector<trie_node*>* tree;//int i=1000;//while(i <= 10000000)//{//s = GetTickCount();//_Make_ip_file(i);//e = GetTickCount();//cout<<"data number = "<<i<<endl;//cout<<"file write= "<<e-s<<endl;//s = GetTickCount();//tree = ip_data_read();//e = GetTickCount();////_Trie_tree_visit(tree,0);//cout<<"file read= "<<e-s<<endl;//cout<<"请输入ip信息如下 123.123.123.222"<<endl;//cin>>ip;//while(ip != "over")//{//s = GetTickCount();//r = _Ip_binary_search(tree,ip);//e = GetTickCount();//cout<<"result = "<<r.second<<endl;//cout<<"ip search = "<<e-s<<endl;//cout<<"请输入ip信息如下 123.123.123.222"<<endl;//cin>>ip;//}//_delete_trie_tree(tree,0);//i = i*10;//}int i;i = 1000000;s = GetTickCount();_Make_ip_file(i);e = GetTickCount();cout<<"data number = "<<i<<endl;cout<<"file write= "<<e-s<<endl;s = GetTickCount();tree = ip_data_read();e = GetTickCount();//_Trie_tree_visit(tree,0);cout<<"file read= "<<e-s<<endl;cout<<"请输入ip信息如下 123.123.123.222"<<endl;cin>>ip;while(ip != "over"){s = GetTickCount();r = _Ip_binary_search(tree,ip);e = GetTickCount();cout<<"result = "<<r.second<<endl;cout<<"ip search = "<<e-s<<endl;cout<<"请输入ip信息如下 123.123.123.222"<<endl;cin>>ip;}_delete_trie_tree(tree,0);//cout<<e-s<<endl;system("pause");return 0;}// function: make filevoid _Make_ip_file(size_t size){ofstream writer ;writer.open("ip.txt");writer.clear();int data ;string place[] = {"北京","天津","上海","重庆"} ;int ip[900];for(int i=0;i<900;i++)ip[i] = i+100;string ziduan = "";for(size_t i =0;i<size;i++){ziduan ="";for(size_t j = 0; j<3; j++){data = ip[rand()%900]  ;ziduan += String::Int_To_String(data)+".";}ziduan += String::Int_To_String(ip[rand()%900])+" "+place[rand()%4] ;writer<<ziduan<<"\n";}writer<<"over"<<endl;writer.close();}// function: read data// input: a file // output: a trie tree point// 功能:将file中的ip信息读到内存中建立的trie tree中，然后返回trie tree 的根;vector<trie_node*>* ip_data_read(){ifstream read;read.open("ip.txt");int * data = new int[4];string place;vector<trie_node*> * tree = new vector<trie_node*>();string ziduan = "";while(true){ziduan ="";read>>ziduan>>place;if( ziduan == "over" )break;//cout<<ziduan<<place<<endl;std::pair<bool,int> r ;string num ;num = ziduan.substr(0,3);r = String::String_into_intNumber(num);if(r.first)data[0] = r.second ;num = ziduan.substr(4,3);r = String::String_into_intNumber(num);if(r.first)data[1] = r.second ;num = ziduan.substr(8,3);r = String::String_into_intNumber(num);if(r.first)data[2] = r.second ;num = ziduan.substr(12,3);r = String::String_into_intNumber(num);if(r.first)data[3] = r.second ;//cout<<data[0]<<" "<<data[1]<<" "<<data[2]<<" "<<data[3]<<" "<<place<<endl;insert_into_trie(tree,data,4,place);}read.close();return tree;}// function: insert keyword into trie treevoid insert_into_trie(vector<trie_node*> *tree,int *data,int length,string place){if(tree != NULL && data != NULL && length == 4 && !place.empty()){std::pair<bool,int> r ;vector<trie_node*> * root = tree ;vector<trie_leaf*> * leaf  ;// strie_node * p ;trie_leaf * L ;int i = 0;while( i < 4 ){if(i < 3){r = binary_search(root,data[i]);// not findif( ! r.first ){p = new trie_node();p->key = data[i];if( i==2 ){p->leaf = new vector<trie_leaf*>();}else{p->child = new vector<trie_node*>();}root->insert(root->begin() + r.second,p);if(i == 2)leaf = p->leaf ;else root = p->child ;}else{if(i == 2)leaf = (*(root->begin()+r.second))->leaf ;else root =(*(root->begin()+r.second))->child ;}}else{r = binary_search_leaf(leaf,data[i]);// not findif( ! r.first ){L = new trie_leaf() ;L -> key = data[i] ;L -> place = place ;leaf->insert(leaf->begin()+r.second,L) ;}}i++;}// e}else{// not insert}}// function: binary_search;// input: an array of node point and a key;// output: if find key, return its subscript; or return its subscript that its should be;// 功能;折半查找，若找到，返回关键字下标，否则返回其应该在的位置（方便插入关键字）//std::pair<bool,vector<tire_node*>::iterator> binary_search(vector<trie_node*> *tree,int key)std::pair<bool,int> binary_search(vector<trie_node*> *tree,int key){if(tree != NULL){if(tree->size() == 0)return std::make_pair(false,tree->end() - tree->begin());vector<trie_node*>::iterator s = tree->begin(),e = tree ->end() -1 ,zhong;if((*s)->key > key)return std::make_pair(false,0);while(s <= e){zhong = s + (e-s)/2;if( key < (*zhong)->key )e = zhong - 1;else if( key > (*zhong)->key)s = zhong + 1;else return std::make_pair(true,zhong - tree->begin());}if(key > (*zhong)->key)zhong++;return std::make_pair(false,zhong - tree->begin());}elsereturn std::make_pair(false,tree->end() - tree->begin());}// function: binary_search;// input: an array of node point and a key;// output: if find key, return its subscript; or return its subscript that its should be;// 功能;折半查找，若找到，返回关键字下标，否则返回其应该在的位置（方便插入关键字）std::pair<bool,int> binary_search_leaf(vector<trie_leaf*> *tree,int key){if(tree != NULL){if(tree->size() == 0)return std::make_pair(false,tree->end() - tree->begin());vector<trie_leaf*>::iterator s = tree->begin(),e = tree ->end() -1 ,zhong;if((*s)->key>key)return std::make_pair(false,0);while(s <= e){zhong = s + (e-s)/2;if( key < (*zhong)->key )e = zhong - 1;else if( key > (*zhong)->key)s = zhong + 1;else return std::make_pair(true,zhong - tree->begin());}if(key > (*zhong)->key)zhong++;return std::make_pair(false,zhong - tree->begin());}elsereturn std::make_pair(false,tree->end() - tree->begin());}// function: _Trie_tree_visit// input:a trie tree' root point// output:void// 功能: 遍历 trie 树void _Trie_tree_visit(vector<trie_node*> *tree,int level){if(tree != NULL){if(level < 2)for(vector<trie_node*>::iterator it = tree->begin();it<tree->end();it++){cout<<"root = "<<(*it)->key<<endl;_Trie_tree_visit((*it)->child,level+1);}else if(level == 2)for(vector<trie_node*>::iterator it = tree->begin();it<tree->end();it++){cout<<"root = "<<(*it)->key<<endl;_Trie_tree_visit_leaf((*it)->leaf,level+1);}}}// function: _Trie_tree_visit// input:a trie tree' root point// output:void// 功能: 遍历 trie 树的叶子void _Trie_tree_visit_leaf(vector<trie_leaf*> *tree,int level){if(tree != NULL && level ==3){for(vector<trie_leaf*>::iterator it = tree->begin();it<tree->end();it++){cout<<"leaf = "<<(*it)->key<<" , place = "<<(*it)->place<<endl;}}}// function: ip binary search// input: a trie tree and a keyword key// output: return pair<bool,string>// 功能：折半查找ip，返回其信息std::pair<bool,string> _Ip_binary_search(vector<trie_node*>* tree,string key){if(tree != NULL && !key.empty()){vector<trie_node*>* root = tree ;vector<trie_leaf*>* leaf;std::pair<bool,int> r;int data[4] ;string ziduan;for(size_t i =0;i<4;i++){ziduan = key.substr(i*4,3);data[i] = String::String_into_intNumber( ziduan ).second;if(i<3){r = binary_search(root,data[i]);if(!r.first)return std::make_pair(false,"not find");if(i<2)root = (*(root->begin()+r.second))->child;else leaf =( *(root->begin()+r.second))->leaf;}else{r = binary_search_leaf(leaf,data[i]);if(!r.first)return std::make_pair(false,"not find");else return std::make_pair(true,(*(leaf->begin()+r.second))->place);}}}else{return std::make_pair(false,"not find");}}// function: delete the space we used;// input: a trie tree root point vector point, and level// output: void// 功能: 释放掉我们开辟的空间，节省空间资源void _delete_trie_tree(vector<trie_node*>* tree,int level){if(tree != NULL && level <3){if(level == 2)for(vector<trie_node*>::iterator it = tree->begin();it<tree->end();it++){((*it)->leaf)->clear();}else for(vector<trie_node*>::iterator it = tree->begin();it<tree->end();it++){_delete_trie_tree((*it)->child,level+1);}if(level == 0)tree->clear();}else{// over}}

 

文本信息如下
ip.txt

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