关于Prim算法求最小生成树的问题

qq_40996817 2018-01-03 12:02:41

#include<iostream>  

#include<fstream>  

using  namespace std;  

  

#define MAX 100  

#define MAXCOST 0x7fffffff  

  

int graph[MAX][MAX];  

  

int prim(int graph[][MAX], int n)  

{  

    int lowcost[MAX];  

    int mst[MAX];  

    int i, j, min, minid, sum = 0;  

    for (i = 2; i <= n; i++)  

    {  

        lowcost[i] = graph[1][i];  

        mst[i] = 1;  

    }  

    mst[1] = 0;  

    for (i = 2; i <= n; i++)  

    {  

        min = MAXCOST;  

        minid = 0;  

        for (j = 2; j <= n; j++)  

        {  

            if (lowcost[j] < min && lowcost[j] != 0)  

            {  

                min = lowcost[j];  

                minid = j;  

            }  

        }  

        cout << mst[minid] << "-" << minid << "=" << min << endl;   

        lowcost[minid] = 0;  

        for (j = 2; j <= n; j++)  

        {  

            if (graph[minid][j] < lowcost[j])  

            {  

                lowcost[j] = graph[minid][j];  

                mst[j] = minid;  

            }  

        }  

    }  

    return sum;  

}  

  

int main()  

{  

    int i, j, k, m, n;  

    int cost;  

    ifstream in("date.txt");  

    in >> m >> n;

    for (i = 1; i <= m; i++)  

    {  

        for (j = 1; j <= m; j++)  

        {  

            graph[i][j] = MAXCOST;  

        }  

    }  

    for (k = 1; k <= n; k++)  

    {  

        in >> i >> j >> cost;  

        graph[i][j] = cost;  

        graph[j][i] = cost;  

    }  

    cost = prim(graph, m);  

    return 0;  

}

我在用这个代码输出最小生成树时，数据的权值为整型时就没有问题，但是如果权值为浮点数时就有问题，不知道怎么修改。。。

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#include<iostream>  
#include<fstream>  
using  namespace std;  
  
#define MAX 100  
#define MAXCOST 0x7fffffff  
  
int graph[MAX][MAX];  
  
int prim(int graph[][MAX], int n)  
{  
    int lowcost[MAX];  
    int mst[MAX];  
    int i, j, min, minid, sum = 0;  
    for (i = 2; i <= n; i++)  
    {  
        lowcost[i] = graph[1][i];  
        mst[i] = 1;  
    }  
    mst[1] = 0;  
    for (i = 2; i <= n; i++)  
    {  
        min = MAXCOST;  
        minid = 0;  
        for (j = 2; j <= n; j++)  
        {  
            if (lowcost[j] < min && lowcost[j] != 0)  
            {  
                min = lowcost[j];  
                minid = j;  
            }  
        }  
        cout << mst[minid] << "-" << minid << "=" << min << endl;   
        lowcost[minid] = 0;  
        for (j = 2; j <= n; j++)  
        {  
            if (graph[minid][j] < lowcost[j])  
            {  
                lowcost[j] = graph[minid][j];  
                mst[j] = minid;  
            }  
        }  
    }  
    return sum;  
}  
  
int main()  
{  
    int i, j, k, m, n;  
    int cost;  
    ifstream in("Karate.txt");  
    in >> m >> n;
    for (i = 1; i <= m; i++)  
    {  
        for (j = 1; j <= m; j++)  
        {  
            graph[i][j] = MAXCOST;  
        }  
    }  
    for (k = 1; k <= n; k++)  
    {  
        in >> i >> j >> cost;  
        graph[i][j] = cost;  
        graph[j][i] = cost;  
    }  
    cost = prim(graph, m);  
    return 0;  
}

qq_40996817 2018-01-03