Graph-005-Finding-a-Path

最新推荐文章于 2025-12-04 17:23:57 发布

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本文介绍了一种基于模板的深度优先搜索（DFS）路径查找算法，该算法应用于图论中寻找从源节点到目标节点的路径。文章详细展示了算法的实现过程，包括使用邻接迭代器遍历图的每个节点，以及如何通过递归调用进行深度优先搜索。此外，还提供了算法的C++代码实现，并通过一个实例演示了如何使用该算法找到并显示从源节点到目标节点的路径。

Path.h

#ifndef INC_06_FINDING_A_PATH_PATH_H
#define INC_06_FINDING_A_PATH_PATH_H

#include <vector>
#include <stack>
#include <iostream>
#include <cassert>

using namespace std;


template <typename Graph>
class Path{

private:
    Graph &G;
    int s;
    bool* visited;
    int * from;

    void dfs( int v ){

        visited[v] = true;

        typename Graph::adjIterator adj(G, v);
        for( int i = adj.begin() ; !adj.end() ; i = adj.next() ){
            if( !visited[i] ){
                from[i] = v;
                dfs(i);
            }
        }
    }

public:
    Path(Graph &graph, int s):G(graph){

        // 算法初始化
        assert( s >= 0 && s < G.V() );

        visited = new bool[G.V()];
        from = new int[G.V()];
        for( int i = 0 ; i < G.V() ; i ++ ){
            visited[i] = false;
            from[i] = -1;
        }
        this->s = s;

        // 寻路算法
        dfs(s);
    }

    ~Path(){

        delete [] visited;
        delete [] from;
    }

    bool hasPath(int w){
        assert( w >= 0 && w < G.V() );
        return visited[w];
    }

    void path(int w, vector<int> &vec){

        stack<int> s;

        int p = w;
        while( p != -1 ){
            s.push(p);
            p = from[p];
        }

        vec.clear();
        while( !s.empty() ){
            vec.push_back( s.top() );
            s.pop();
        }
    }

    void showPath(int w){

        vector<int> vec;
        path( w , vec );
        for( int i = 0 ; i < vec.size() ; i ++ ){
            cout<<vec[i];
            if( i == vec.size() - 1 )
                cout<<endl;
            else
                cout<<" -> ";
        }
    }
};

#endif

main.cpp

#include <iostream>
#include "SparseGraph.h"
#include "DenseGraph.h"
#include "ReadGraph.h"
#include "Path.h"

using namespace std;


int main() {

    string filename = "testG2.txt";
    SparseGraph g = SparseGraph(7, false);
    ReadGraph<SparseGraph> readGraph(g, filename);
    g.show();
    cout<<endl;

    Path<SparseGraph> dfs(g,0);
    cout<<"DFS : ";
    dfs.showPath(6);

    return 0;
}