在C ++中寻找可解决此问题的特定设计模式

时间：2019-03-26 21:28:51

标签： c++ algorithm design-patterns data-structures

我正在寻找可以解决此问题的C ++中的 特定设计模式。

。

我想设计一个情节提要。我们的情节提要 包含任意许多笔记（想象一下，就像将便签放在板上）。 每个笔记都有一个标题，一个文本和一组标签。例如。 -标题：“ Test Traceplayer” -文本：“为spark核心框架的Traceplayer类执行单元测试。” -标签：{“单元测试”，“ traceplayer”，“测试”，“火花核心”}

我们的分镜脚本应该使我们能够按标题，文本和标签搜索注释。 例如。：   searchByTitle（“测试Traceplayer”）   searchByTag（{“ testing”，“ unit test”}）   searchByText（“为spark核心框架的Traceplayer类执行单元测试。”） 为了简单起见，我们不想在以下情况下进行任何相似性或前缀匹配 搜索标题，标签或文本。只有完全匹配才能给出结果。

我有许多解决此问题的解决方案O（1）搜索复杂性，但是任何人都可以提出解决该问题的任何“设计模式”。

解决三个STL映射问题并获得恒定的时间搜索复杂性

寻找可以解决此问题的特定设计模式。

我已经使用3个STL Map解决了这个问题，并且解决方案获得了O（1）搜索复杂性

#include <iostream>
#include <vector>
#include <map>

#define INPUT 8 

class Note {
public:
    string Tital;
    string Text;
    vector<string> vec;
    Note(){
        Tital = "\0";
        Text = "\0";
    }
};

class storyBoard{
public:
    void AddNote(string Tital,string Text,vector<string> vec );
    void RemoveByTital(string &tital);
    void PrintStoredData();
    Note* searchByTitle(string titleSearch);

    Note* searchByText(string text_);
    vector<Note*> searchByTag(string titleSearch);

    void printSlip(Note *tm);
    storyBoard(){}
private:

    std::map<string,Note *> TitalMap;
    std::map<string,Note *> TextMap;
    std::map<string,std::vector<Note *> > TagsMap;
};


Note* storyBoard::searchByTitle(string titleSearch){
    auto it_v = TitalMap.find(titleSearch);
    if (it_v != TitalMap.end()){
        cout<< "Tital search result is below:-"<<endl;
        return it_v->second;
    } else {
        cout <<"data "<<titleSearch << "  Not found"<<endl;
        return NULL;
    }
}

Note* storyBoard::searchByText(string titleSearch){
    auto it_v = TextMap.find(titleSearch);
    if (it_v != TextMap.end()){
        cout<< "Text search result is below:-"<<endl;
        return it_v->second;
    } else {
        cout <<"data "<<titleSearch << "  Not found"<<endl;
        return NULL;
    }
}

vector<Note*> storyBoard::searchByTag(string tagSearch){
    auto it_v = TagsMap.find(tagSearch);
    if (it_v != TagsMap.end()){
        cout<< "Tag search result is below:-"<<endl;
        return it_v->second;
    } else {
        cout <<"data "<<tagSearch << "  Not found"<<endl;
        vector<Note*> del;
        return del;
    }
}


void storyBoard::AddNote(string Tital, string Text, vector<string> v){
   Note *note = new Note;
   note->Tital = Tital;
   note->Text = Text;
   note->vec = v;

   TitalMap[note->Tital] = note;
   TextMap[note->Text] = note;

   for (auto it = note->vec.begin(); it != note->vec.end(); ++it){
       //check that is tags already 
       auto it_v = TagsMap.find(*it);
       if (it_v != TagsMap.end()){
           it_v->second. push_back(note);
       } else {
           vector<Note *> &v = TagsMap[*it];
           v.push_back(note);
       }
    }   
}

void storyBoard::printSlip(Note *tm){
    cout << "Tital=" << tm->Tital <<endl 
        << "Text=" <<  tm->Text <<endl
        << "Tags = ";
    for (auto it = tm->vec.begin(); it != tm->vec.end(); ++it){
        cout<< *it<<"\t";
    }    
    cout<<endl<<endl;
}

void storyBoard::PrintStoredData(){
    for(auto tm : TitalMap){
        printSlip(tm.second);
    }
    cout<<endl; 
}

void feed_data_for_testing(storyBoard &Sb);
void TestCase(storyBoard &Sb);

int main() {
    storyBoard Sb;
    feed_data_for_testing(Sb);

    Sb.PrintStoredData(); /*Print all contain data */
    cout<<"************* From Here start searching ************"<<endl;
    TestCase(Sb);
    return 0;
}

void TestCase(storyBoard &Sb){    
    Note* obj = Sb.searchByTitle("Tital-3");
    if(obj != NULL){
        Sb.printSlip(obj);
    }

    obj = Sb.searchByText("Text-4");
    if(obj != NULL){
        Sb.printSlip(obj);
    }

    vector<Note *> vec = Sb.searchByTag("tag-3");
    if(vec.size() !=0){
        for (auto it = vec.begin(); it != vec.end(); ++it){
            //cout<<(*it)->Tital << "\t";
            Sb.printSlip(*it);
        } 
    }   
}

void feed_data_for_testing(storyBoard &Sb){
    vector<string> tags ;
    int count =INPUT;
    for(int i =1;i<=count;i++){
        string tital = "Tital-" + std::to_string(i);
        string text = "Text-" + std::to_string(i);
        tags.clear();
        for(int j =1;j<=i;j++){
            string tag_ = "tag-" +  std::to_string(j);
            tags.push_back(tag_);
        }
        Sb.AddNote(tital,text,tags);
    }
}

我正在寻找一种解决该问题的设计模式。

2 个答案:

答案 0 :(得分：0)

我在以下几点更新您的代码：-

  1. 将类转换为单例，以便数据为每种类型维护单个映射
  2. 将地图更改为unorder_map 
#define INPUT 8 
using namespace std;

/*use class to store single slip data*/
class Note {
public:
    string Tital;
    string Text;
    vector<string> vec;
    Note(){ //constructor to initialize data zero
        Tital = "\0";
        Text = "\0";
    }
};
/*create a singalton pattern class so that create only one data storage*/
class storyBoard{
public:
    static storyBoard* getInstance(){
        storyBoard* Instance= instance.load();
        if ( !Instance ){
            std::lock_guard<std::mutex> myLock(lock);
            Instance= instance.load();
            if( !Instance ){
              Instance= new storyBoard();
              instance.store(Instance);
            }
        }   
        return Instance;
    }

    void AddNote(string Tital,string Text,vector<string> vec );
    void RemoveByTital(string &tital);
    void PrintStoredData();
    Note* searchByTitle(string titleSearch);

    Note* searchByText(string text_);
    vector<Note*> searchByTag(string titleSearch);

    void printSlip(Note *tm);
private:
    storyBoard()= default;
    ~storyBoard()= default;
    storyBoard(const storyBoard&)= delete;
    storyBoard& operator=(const storyBoard&)= delete;

    static std::atomic<storyBoard*> instance;
    static std::mutex lock;
    std::unordered_map<string,Note *> TitalMap;
    std::unordered_map<string,Note *> TextMap;
    std::unordered_map<string,std::vector<Note *> > TagsMap;
};


std::atomic<storyBoard*> storyBoard::instance;
std::mutex storyBoard::lock;

Note* storyBoard::searchByTitle(string titleSearch){
    auto it_v = TitalMap.find(titleSearch);
    if (it_v != TitalMap.end()){
        cout<< "Tital search result is below:-"<<endl;
        return it_v->second;
    } else {
        cout <<"data "<<titleSearch << "  Not found"<<endl;
        return NULL;
    }
}

Note* storyBoard::searchByText(string titleSearch){
    auto it_v = TextMap.find(titleSearch);
    if (it_v != TextMap.end()){
        cout<< "Text search result is below:-"<<endl;
        return it_v->second;
    } else {
        cout <<"data "<<titleSearch << "  Not found"<<endl;
        return NULL;
    }
}

vector<Note*> storyBoard::searchByTag(string tagSearch){
    auto it_v = TagsMap.find(tagSearch);
    if (it_v != TagsMap.end()){
        cout<< "Tag search result is below:-"<<endl;
        return it_v->second;
    } else {
        cout <<"data "<<tagSearch << "  Not found"<<endl;
        vector<Note*> del;
        return del;
    }
}


void storyBoard::AddNote(string Tital, string Text, vector<string> v){
   Note *note = new Note;
   note->Tital = Tital;
   note->Text = Text;
   note->vec = v;

   TitalMap[note->Tital] = note;
   TextMap[note->Text] = note;

   for (auto it = note->vec.begin(); it != note->vec.end(); ++it){
       //check that is tags already 
       auto it_v = TagsMap.find(*it);
       if (it_v != TagsMap.end()){
           it_v->second. push_back(note);
       } else {
           vector<Note *> &v = TagsMap[*it];
           v.push_back(note);
       }
    }   
}

void storyBoard::printSlip(Note *tm){
    cout << "Tital=" << tm->Tital <<endl 
        << "Text=" <<  tm->Text <<endl
        << "Tags = ";
    for (auto it = tm->vec.begin(); it != tm->vec.end(); ++it){
        cout<< *it<<"\t";
    }    
    cout<<endl<<endl;
}

void storyBoard::PrintStoredData(){
    for(auto tm : TitalMap){
        printSlip(tm.second);
    }
    cout<<endl; 
}
/**temporary function only use for testing*/
void TestCase(){    
    storyBoard *Sb = storyBoard::getInstance();
    Note* obj = Sb->searchByTitle("Tital-3");
    if(obj != NULL){
        Sb->printSlip(obj);
    }

    obj = Sb->searchByText("Text-4");
    if(obj != NULL){
        Sb->printSlip(obj);
    }

    vector<Note *> vec = Sb->searchByTag("tag-3");
    if(vec.size() !=0){
        for (auto it = vec.begin(); it != vec.end(); ++it){
            //cout<<(*it)->Tital << "\t";
            Sb->printSlip(*it);
        } 
    }   
}
/**temporary function only use for testing*/
void feed_data_for_testing(){
    storyBoard *Sb = storyBoard::getInstance();
    vector<string> tags ;
    int count =INPUT;
    for(int i =1;i<=count;i++){
        string tital = "Tital-" + std::to_string(i);
        string text = "Text-" + std::to_string(i);
        tags.clear();
        for(int j =1;j<=i;j++){
            string tag_ = "tag-" +  std::to_string(j);
            tags.push_back(tag_);
        }
        Sb->AddNote(tital,text,tags);
    }
}

int main() {
    storyBoard *Sb = storyBoard::getInstance();
    feed_data_for_testing();

    Sb->PrintStoredData(); /*Print all contain data */
    cout<<"************* From Here start searching ************"<<endl;
    TestCase();
    return 0;
}

答案 1 :(得分：0)

我认为您的面试官错误地使用了设计模式一词代替了惯用语。

您的代码的一个主要问题（可能是拒绝的原因）是使用经典C ++习惯用法的内存处理：

  • 使用智能指针来管理笔记的寿命
  • rule of 3 (or 5)处理StoryBoard对象的复制/分配（/移动）

请注意，使用智能指针只是管理内存的一种方法。您也可以使用其他习语：

  • 注释区域和引用哈希表中的区域的注释
  • ...

此问题解决后，您将遇到一些小问题：

  • 返回指针而不是引用，StoryBoard是内存的所有者，您不应返回调用者可能无意中释放的指针。
  • 没有const访问器（返回const引用）
  • 可以分解的重复代码

如果我在解释面试官所说的内容时没有错，则应将此问题移至codereview.stackexhange.com

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