poj 2387 Til the Cows Come Home

#include <iostream>        //单源顶点最短路径：迪杰斯特拉（Dijkstra）算法
using namespace std;                                

const int MaxWeight=1000002;    //最大值应该是1000*100+1        
int  Vertex,edge[1002][1002],distD[1002],i,j;
void init()
{
    for(i=1;i<=Vertex;i++)        //结点坐标都是从1开始的
        for(j=1;j<=Vertex;j++)
        {
            if(i==j)
                edge[i][j]=0;
            else
                edge[i][j]=MaxWeight;
        }
}
void ShortestPath_Dijstra(int v)     //从源点v到其余各顶点的最短路径长度
{
    int min,u,S[1002],pathD[1002];    
    for(i=1;i<=Vertex;i++)
    {
        distD[i]=edge[v][i];S[i]=0;
        if(i!=v&&distD[i]<MaxWeight)
            pathD[i]=v;
        else
            pathD[i]=-1;
    }
    S[v]=1;
    for(i=1;i<Vertex;i++)
    {
        min=MaxWeight;
        for(j=1;j<=Vertex;j++)
            if(!S[j]&&distD[j]<min)
            {
                u=j;min=distD[j];
            }
        S[u]=1;
        for(j=1;j<=Vertex;j++)
            if(!S[j]&&edge[u][j]<MaxWeight&&distD[u]+edge[u][j]<distD[j])
            {
                distD[j]=distD[u]+edge[u][j];pathD[j]=u;
            }
    }
    printf("%d\n",distD[1]);
}
int main()
{
    int t,a,b,c;
    cin>>t>>Vertex;    
    init();
    while(t--)
    {
        cin>>a>>b>>c;
        if(edge[a][b]>c)        //有重边
            edge[a][b]=edge[b][a]=c;
    }
    ShortestPath_Dijstra(Vertex);    
    
    return 0;
}