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그래프에서 최단 거리 찾기 알고리즘, 다익스트라 알고리즘 [C++ 소스] 본문

C++/디딤돌 자료구조와 알고리즘 with C++

그래프에서 최단 거리 찾기 알고리즘, 다익스트라 알고리즘 [C++ 소스]

Only 프로그램 소스 언제나휴일 2016.06.12 22:03

그래프에서 최단 거리 찾기 알고리즘

다익스트라 알고리즘 [C++ 소스]


다익스트라 알고리즘.zip



"본문 내용"은 언제나 휴일 본 사이트에 있습니다.


//Edge.h

#pragma once

#include <string>

using namespace std;

class Edge

{

    string vt1;

    string vt2;

    int weight;

public:

    Edge(string vt1,string vt2,int height);

    bool Exist(string vt)const;

    bool Exist(string vt1, string vt2)const;

    string Other(string vt)const;

    void View()const;

    int GetWeight()const;

};


//Edge.cpp

#include "Edge.h"

#include <iostream>

using namespace std;

 

Edge::Edge(string vt1,string vt2,int weight)

{

    this->vt1 = vt1;

    this->vt2 = vt2;

    this->weight = weight;

}

 

bool Edge::Exist(string vt)const

{

    return (vt1 == vt)||(vt2==vt);

}

 

bool Edge::Exist(string vt1, string vt2)const

{

    return Exist(vt1) && Exist(vt2);

}

string Edge::Other(string vt)const

{

    if(vt1 == vt)

    {

        return vt2;

    }

    if(vt2 == vt)

    {

        return vt1;

    }

    return "";

}

 

void Edge::View()const

{

    cout<<"("<<vt1<<","<<vt2<<","<<weight<<")";

}

 

int Edge::GetWeight()const

{

    return weight;

}


//Graph.h

#pragma once

#include "Edge.h"

#include <iostream>

#include <vector>

using namespace std;

 

typedef vector<string> Vertexs;

typedef Vertexs::iterator VIter;

typedef Vertexs::const_iterator CVIter;

 

typedef vector<Edge *> Edges;

typedef Edges::iterator EIter;

typedef Edges::const_iterator CEIter;

 

class Graph

{

    Vertexs vertexs;

    Edges edges;

public:   

    ~Graph(void);   

    bool AddVertex(string vt);

    bool Exist(string vt)const;

    bool AddEdge(string vt1, string vt2,int weight);//간선 추가

    bool Exist(string vt1,string vt2)const;

    void ViewNeighbors()const;

    void ViewNeighbor(string vt)const;

    Vertexs FindNeighbors(string vt)const;

    Edges FindEdges(string vt)const;

};



//Graph.cpp

#include "Graph.h"

#include <string.h>

#include <algorithm>

 

Graph::~Graph(void)

{

    EIter seek = edges.begin();

    EIter last = edges.end();

    for(  ;seek != last; ++seek)

    {

        delete (*seek);//간선 소멸

    }   

}

 

bool Graph::AddVertex(string vt)

{

    if(Exist(vt))

    {

        return false;

    }

    vertexs.push_back(vt);

    return true;

}

 

bool Graph::Exist(string vt)const

{

    return find(vertexs.begin(),vertexs.end(),vt) != vertexs.end();

}

 

bool Graph::AddEdge(string vt1, string vt2,int weight)//간선 추가

{

    if(Exist(vt1)&&Exist(vt2))

    {

        if(Exist(vt1,vt2))

        {

            return false;

        }

 

        CEIter seek = edges.begin();

        CEIter last = edges.end();

        for(  ;seek != last; ++seek)

        {

            if((*seek)->GetWeight()>=weight)

            {

                break;

            }

        }   

        edges.insert(seek,new Edge(vt1,vt2,weight));

        return true;

    }

    return false;

}

 

bool Graph::Exist(string vt1,string vt2)const

{

    CEIter seek = edges.begin();

    CEIter last = edges.end();

    for(  ;seek != last; ++seek)

    {

        if((*seek)->Exist(vt1,vt2))

        {

            return true;

        }

    }   

    return false;

}

 

void Graph::ViewNeighbors()const

{

    cout<<"=== 이웃 정점 ==="<<endl;

    CVIter seek = vertexs.begin();

    CVIter last = vertexs.end();

    for(   ;seek != last; ++seek)

    {

        cout<<(*seek)<<"의 이웃: ";

        ViewNeighbor(*seek);//i정점의 이웃 보여주기

    }

    cout<<endl;

}

 

void Graph::ViewNeighbor(string vt)const

{

    CEIter seek = edges.begin();

    CEIter last = edges.end();

    for(  ;seek != last; ++seek)

    {

        if((*seek)->Exist(vt))

        {

            cout<<(*seek)->Other(vt)<<" ";

        }

    }

    cout<<endl;

}

 

Vertexs Graph::FindNeighbors(string vt)const

{

    Vertexs neighbors;

    CEIter seek = edges.begin();

    CEIter last = edges.end();

 

    for(  ;seek != last; ++seek)

    {

        if((*seek)->Exist(vt))

        {

            neighbors.push_back((*seek)->Other(vt));

        }

    }   

    return neighbors;

}

 

Edges Graph::FindEdges(string vt)const

{

    Edges neighbors;

    CEIter seek = edges.begin();

    CEIter last = edges.end();

    for(  ;seek != last; ++seek)

    {

        if((*seek)->Exist(vt))

        {

            neighbors.push_back(*seek);

        }

    }   

    return neighbors;

}


//Heuristic.h

#pragma once

#include "Graph.h"

#include <vector>

using namespace std;

 

typedef vector<string> Foots;

typedef Foots::iterator FIter;

typedef Foots::const_iterator CFIter;

 

class Heuristic;

typedef vector<Heuristic *> Heues;

typedef Heues::iterator HIter;

typedef Heues::const_iterator CHIter;

 

class Heuristic

{

    Graph *graph;       

    Foots foots;

    int weight;

public:

    Heuristic(Graph *graph, string start);   

    Heues EnumNext();   

    void View()const;   

    int GetWeight()const;

    string GetLastVertex()const;

private:

    Heuristic(const Heuristic *bheu,string vt,int weight);

};


//Heuristic.cpp

#include "Heuristic.h"

#include <algorithm>

 

Heuristic::Heuristic(Graph *graph,string start)

{

    this->graph = graph;

    foots.push_back(start);

    weight = 0;

}

 

Heues Heuristic::EnumNext()

{

    Heues nheues;

    string last_foot = (*foots.rbegin());

    Edges edges = graph->FindEdges(last_foot);

 

    EIter eseek = edges.begin();

    EIter elast = edges.end();

    for(  ;eseek != elast; ++eseek)

    {

        string other = (*eseek)->Other(last_foot);//간선의 나머지 정점 구하기

        if(find(foots.begin(), foots.end(),other) == foots.end())//방문한 적이 없으면

        {

            Heuristic * nheu = new Heuristic(this,other,(*eseek)->GetWeight());

            HIter hseek = nheues.begin();

            HIter hlast = nheues.end();

            for(  ;hseek != hlast; ++hseek)

            {

                if((*hseek)->GetWeight()>=nheu->GetWeight())

                {

                    break;

                }

            }   

            nheues.insert(hseek,nheu);//*seek를 추가 방문하는 새로운 경험을 생성           

        }

    }   

    return nheues;

}

 

 

 

 

void Heuristic::View()const

{

    cout<<"cost "<<weight<<" :";

    CFIter seek = foots.begin();

    CFIter last = foots.end();

    for(  ;seek != last; ++seek)

    {

        cout<<(*seek)<<" ";

    }

    cout<<endl;

}

 

int Heuristic::GetWeight()const

{

    return weight;

}

 

string Heuristic::GetLastVertex()const

{

    return (*foots.rbegin());

}

 

Heuristic::Heuristic(const Heuristic *bheu,string vt,int weight)

{

    this->graph = bheu->graph;

    foots = bheu->foots;   

    this->weight = bheu->weight + weight;//경로의 비용을 추가

    foots.push_back(vt);//vt를 방문한 행적에 추가

}



//Program.cpp

#include "Heuristic.h"

#include <queue>

using namespace std;

struct HGreater

{

    bool operator()(const Heuristic *h1, const Heuristic *h2) const

    {

        return h1->GetWeight()> h2->GetWeight();

    }

};

 

 

int main()

{

    Graph *graph = new Graph();//그래프 동적 생성

    graph->AddVertex("A");

    graph->AddVertex("B");

    graph->AddVertex("C");

    graph->AddVertex("D");

    graph->AddVertex("E");

    graph->AddVertex("F");

    graph->AddVertex("G");

    graph->AddVertex("H");

    graph->AddVertex("I");

 

    graph->AddEdge("A", "B", 3);//간선 추가

    graph->AddEdge("A", "C", 4);//간선 추가

    graph->AddEdge("B", "C", 4);//간선 추가

    graph->AddEdge("B", "D", 3);//간선 추가

    graph->AddEdge("B", "E", 3);//간선 추가

    graph->AddEdge("C", "D", 3);//간선 추가

    graph->AddEdge("C", "I", 4);//간선 추가

    graph->AddEdge("D", "E", 4);//간선 추가

    graph->AddEdge("D", "F", 6);//간선 추가

    graph->AddEdge("D", "H", 2);//간선 추가

    graph->AddEdge("D", "I", 5);//간선 추가

    graph->AddEdge("E", "F", 5);//간선 추가

    graph->AddEdge("F", "G", 4);//간선 추가

    graph->AddEdge("G", "H", 3);//간선 추가

    graph->AddEdge("H", "I", 5);//간선 추가   

    graph->ViewNeighbors();

 

    priority_queue<Heuristic *,vector<Heuristic *>, HGreater > hq;

    Heues htable;

    Heues all;   

    Heuristic *heu = new Heuristic(graph,"A");//초기 경험 정보를 생성

    hq.push(heu);//큐에 보관

    while(hq.empty() == false) //반복(큐가 비어 있지 않다면)

    {

        heu = hq.top();//큐에서 경험 정보 꺼내옮

        hq.pop();

        all.push_back(heu);

        cout<<"찾는중 ";

        heu->View();

 

        Heues nheues = heu->EnumNext();//큐에서 꺼내온 경험 정보에서 다음 경험 목록 조사       

        HIter seek = nheues.begin();

        HIter last = nheues.end();       

 

        for(  ;seek != last; ++seek)//반복(다음 경험 목록을 순차적으로 반복)

        {

            HIter hseek = htable.begin();

            HIter hlast = htable.end();

 

            string nvt = (*seek)->GetLastVertex();

            bool check = true;

 

            for(   ;hseek != hlast; ++hseek)

            {

                string hvt = (*hseek)->GetLastVertex();

                if(nvt == hvt)

                {

                    if((*seek)->GetWeight()<(*hseek)->GetWeight())

                    {                                               

                        check = false;                       

                    }

                    break;

                }

            }

 

            if(hseek == hlast)

            {

                hq.push(*seek);//큐에 보관

                htable.push_back(*seek);

            }

            else

            {

                if(check == false)

                {

                    htable.erase(hseek);

                    htable.push_back(*seek);

                    hq.push(*seek);

                }  

            }

        }       

    }

 

 

    HIter hseek = htable.begin();

    HIter hlast = htable.end();

    cout<<"A에서의 최단 경로"<<endl;

    for(   ;hseek != hlast; ++hseek)

    {

        (*hseek)->View();

    }

 

    HIter aseek = all.begin();

    HIter alast = all.end();

    for(   ;aseek != alast; ++aseek)

    {

        delete (*aseek);

    }

    delete graph;

    return 0;

}

 

다음은 코드에서 사용한 그래프와 다익스트라 알고리즘으로 경로를 찾은 논리적 그림입니다.

그래프와 정점에서의 최단 거리


▷ 실행 결과

=== 이웃 정점 ===

A의 이웃: B C

B의 이웃: E D A C

C의 이웃: D I B A

D의 이웃: H C B E I F

E의 이웃: B D F

F의 이웃: G E D

G의 이웃: H F

H의 이웃: D G I

I의 이웃: C H D

 

찾는중 cost 0 :A

찾는중 cost 3 :A B

찾는중 cost 4 :A C

찾는중 cost 6 :A B D

찾는중 cost 6 :A B E

찾는중 cost 8 :A B D H

찾는중 cost 8 :A C I

찾는중 cost 11 :A B E F

찾는중 cost 11 :A B D H G

찾는중 cost 12 :A B D F

A에서의 최단 경로

cost 3 :A B

cost 4 :A C

cost 6 :A B D

cost 6 :A B E

cost 8 :A C I

cost 8 :A B D H

cost 11 :A B E F

cost 11 :A B D H G 



프로그래밍 언어 및 기술 학습, 무료 동영상 강의 언제나 휴일

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