hdu1385 Minimum Transport Cost 字典序最小的最短路径 Floyd

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int N =110, INF=1000000;
int Map[N][N], dist[N][N], pre[N][N], c[N];
//pre存贮i到j路径中j的前一点
int n;
void floyd()
{
    int i,j,k;
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=n;j++)
        {
            dist[i][j]=Map[i][j];
            pre[i][j]=j;
        }
    }
    for(k=1;k<=n;k++)
        for(i=1;i<=n;i++)
            for(j=1;j<=n;j++)
            {
                //if(dist[i][k]==INF||dist[k][j]==INF) continue;
                int d=dist[i][k]+dist[k][j]+c[k];
                if(d<dist[i][j])
                {
                    dist[i][j]=d;
                    pre[i][j]=pre[i][k];
                }
                else if(d==dist[i][j])
                {
                    if(pre[i][j]>pre[i][k])
                        pre[i][j]=pre[i][k];
                }
            }
}
int main()
{
    //freopen("test.txt","r",stdin);
    int i,j,k,a,b;
    while(scanf("%d",&n)!=EOF)
    {
        if(!n) break;
        for(i=1;i<=n;i++)
            for(j=1;j<=n;j++)
        {
            scanf("%d",&Map[i][j]);
            if(Map[i][j]<0) Map[i][j]=INF;
        }
        for(i=1;i<=n;i++) scanf("%d",&c[i]);
        while(scanf("%d%d",&a,&b))
        {
            if(a==-1&&b==-1) break;
            floyd();
            printf("From %d to %d :\n",a,b);
            printf("Path: %d",a);
            k=a;
            while(k!=b){printf("-->%d",pre[k][b]);k=pre[k][b];}
            printf("\n");
            printf("Total cost : %d\n",dist[a][b]);
            printf("\n");
        }
    }
    return 0;
}

const int N =1010, INF=0x3f3f3f3f;
int Map[N][N], dist[N][N], pre[N][N];
//pre存贮i到j路径中j的前一点
int n;
void floyd()
{
    int i,j,k;
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=n;j++)
        {
            dist[i][j]=Map[i][j];
            pre[i][j]=i;
        }
    }
    for(k=1;k<=n;k++)
        for(i=1;i<=n;i++)
            for(j=1;j<=n;j++)
                if(dist[i][k]!=INF&&dist[k][j]!=INF&&
                   dist[i][k]+dist[k][j]<dist[i][j])
                {
                    dist[i][j]=dist[i][k]+ dist[k][j];
                    pre[i][j]=pre[k][j];
                }
}
void init()
{
    for(int i=1;i<=n;i++)
        for(int j=1;j<=n;j++)
            Map[i][j]=INF;
}