普里姆（Prim）算法

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/*********************普里姆(Prim)算法******************///网类template<class Type>class NetGraph{private:    Type vexs[MAX];//顶点表    int  arc[MAX][MAX];//邻接矩阵    int numVertexes, numEdges;//当前网中节点、边数量    int getPosition(Type el);//获取数据el在顶点表中的位置    Type readType();//外界读取一个数据public:    NetGraph();//创建网图    ~NetGraph(){}//析构函数    void print();//打印邻接矩阵    void MiniSpanTree_Prim();//Prim算法生成最小生成树};//获取数据el在顶点表中的位置template<class Type>int NetGraph<Type>::getPosition(Type el){    int i;    for (i = 0; i < this->numVertexes; i++)    {        if (this->vexs[i] == el)            return i;    }    return -1;}//外界读取一个数据template<class Type>Type NetGraph<Type>::readType(){    Type ch;    cout << "Input a edge data: ";    cin >> ch;    return ch;}//创建网图(手动输入)template<class Type>NetGraph<Type>::NetGraph(){    int i,j;    Type c1, c2;    int p1, p2;    int weight;//用于存储权值    cout << "Input Vertexes number: ";    cin >> this->numVertexes;    cout << "Input Edge number: ";    cin >> this->numEdges;    //检测顶点、边输入合法性    if (this->numVertexes < 1 || this->numEdges<1 || this->numEdges> this->numVertexes*(this->numVertexes - 1))    {        cout << "Error input!" << endl;        return;    }    //顶点初始化    for (i = 0; i < this->numVertexes; i++)    {        cout << "Input a Type data" << i + 1 << ": ";        cin >> this->vexs[i];    }    //邻接矩阵初始化    for (i = 0; i < this->numVertexes; i++)    {        for (j = 0; j < this->numVertexes; j++)        {            if (i == j)                this->arc[i][j] = 0;            else                this->arc[i][j] = 65535;        }    }    //边初始化    for (i = 0; i < this->numEdges; i++)    {        c1 = readType();        c2 = readType();        p1 = getPosition(c1);        p2 = getPosition(c2);        if (p1 == -1 || p2 == -1 || p1 == p2)        {            cout << "Earror Input!" << endl;            return;        }        cout << "Input a weight value: ";        cin >> weight;        this->arc[p1][p2] = weight;        this->arc[p2][p1] = weight;    }}//打印邻接矩阵template<class Type>void NetGraph<Type>::print(){    cout << "******************************" << endl;    cout << "打印邻接矩阵" << endl;    int i, j;    for (i = 0; i < this->numVertexes; i++)    {        for (j = 0; j < this->numVertexes; j++)            cout << this->arc[i][j] << '\t';        cout << endl;    }}//Prim算法生成最小生成树template<class Type>void NetGraph<Type>::MiniSpanTree_Prim(){    int min, i, j, k;    int adjvex[MAX];//保存相关顶点下标    int lowcost[MAX];//保存相关顶点间边的权值    lowcost[0] = 0;//初始化第一个权值为0，即第一个元素加入生成树    adjvex[0] = 0;//初始化第一个顶点下表为0    for (i = 1; i < this->numVertexes; i++)    {        lowcost[i] = this->arc[0][i];//将第一个元素与之有关的权值存入数组        adjvex[i] = 0;//初始化都为第一个元素的下标    }    for (i = 0; i < this->numVertexes; i++)    {        min = 65535;//初始化最小权值为65535        j = 1; k = 0;        while (j < this->numVertexes)        {            if (lowcost[j] != 0 && lowcost[j] < min)            {                min = lowcost[j];                k = j;            }            j++;        }        cout << "(" << adjvex[k] << ", " << k << ") ";        lowcost[k] = 0;//当前顶点的权值设置为0，表示此顶点已经完成任务        for (j = 1; j < this->numVertexes; j++)        {            if (lowcost[j] != 0 && this->arc[k][j] < lowcost[j])            {                lowcost[j] = this->arc[k][j];                adjvex[j] = k;            }        }    }}//测试程序int main(){    NetGraph<char> graph;    graph.print();    graph.MiniSpanTree_Prim();    return 0;}
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