货币套汇（图路径）

#include <iostream>
#include <string>
using namespace std;

class Graph
{
private:
    int vexnum;     //顶点数
    int arcnum;     //边数
    bool *visit;    //访问数组
    double **array; //邻接矩阵
    string *vex;    //边
    int *road;      //记录走过的路
    int num;
    void DFS(int v)
    {
    }
    int Index(string s)
    {
        for (int i = 0; i < vexnum; i++)
        {
            if (vex[i] == s)
            {
                return i;
            }
        }
        return -1;
    }

public:
    Graph()
    {
        cin >> vexnum >> arcnum;
        vex = new string[vexnum];
        visit = new bool[vexnum];
        road = new int[vexnum];
        array = new double *[vexnum];
        for (int i = 0; i < vexnum; i++)
        {
            cin >> vex[i];
            array[i] = new double[vexnum];
            visit[i] = 0;
            road[i] = 0;
            for (int j = 0; j < vexnum; j++)
            {
                array[i][j] = 0;
            }
        }
        for (int i = 0; i < arcnum; i++)
        {
            string str1, str2;
            double weight;
            cin >> str1 >> weight >> str2;
            int pos1 = Index(str1), pos2 = Index(str2);
            array[pos1][pos2] = weight;
        }
    }
    ~Graph()
    {
        delete[] vex;
        delete[] road;
        delete[] visit;
        for (int i = 0; i < vexnum; i++)
        {
            delete array[i];
        }
        delete array;
    }
    void DFS(int v)
    {
        visit[v] = true;
        road[num++] = v; //记录每一条经过的边，以便后面的计算
        for (int i = 0; i < vexnum; i++)
        {
            if (visit[i] == 0 && array[v][i] != 0) //若无访问且有边相接，继续遍历
            {
                DFS(i);
            }
        }
    }
    void DFS_Traverse()
    {
        for (int i = 0; i < vexnum; i++)
        {
            num = 0;
            DFS(i);
            for (int k = 0; k < num; k++)
            {
                //判断与起点是否构成环，若构成环则进行计算操作
                if (array[road[k]][i] != 0)
                {
                    double result = 1;
                    for (int j = 0; j < k; j++)
                    {
                        result *= array[road[j]][road[j + 1]]; //一直乘到最后一个点
                    }
                    result *= array[road[k]][road[0]];         //最后从最后一个点回到起点，构成一个环，将其乘起来
                    if(result>1)
                    {
                        cout<<"YES"<<endl;
                    }
                }
            }
        }
        for(int i=0;i<vexnum;i++)
        {
            visit[i]=0;
            road[i]=0;
        }
        cout<<"NO"<<endl;
    }
};


int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        Graph G;
        G.DFS_Traverse();
    }
    return 0;
}