poj 2457 Part Acquisition dij

dij+记录路径

#include <stdio.h>
#define inf 0x3f3f3f3f

int k,n,path[1005],dis[1005],map[1005][1005];

void dij()
{
    int i,j,min,minj,vis[1005];
    for (i=1;i<=k;i++)
    {
        dis[i]=map[1][i];
        vis[i]=0;
        path[i]=i;
    }
    vis[i]=1;
    for (i=2;i<=k;i++)
    {
        for (j=1,min=inf;j<=k;j++)
        {
            if(!vis[j]&&dis[j]<min)
            {
                min=dis[j];
                minj=j;
            }
        }
        vis[minj]=1;
        for (j=1;j<=k;j++)
        {
            if(!vis[j]&&dis[j]>dis[minj]+map[minj][j])
            {
                dis[j]=dis[minj]+map[minj][j];
                path[j]=minj;
            }
        }
    }
}

void f()
{
    int i=1,j,x=k,ans[1005];
    ans[0]=k;
    while (path[x]!=x)
    {
        ans[i++]=path[x];
        x=path[x];
    }
    printf("%d\n",i+1);
    ans[i]=1;
    for (j=i;j>=0;j--)
        printf("%d\n",ans[j]);
}

int main()
{
    int i,j,a,b;
    scanf("%d%d",&n,&k);
    for (i=0;i<=k;i++)
    {
        for (j=0;j<=k;j++)
            map[i][j]=inf;
    }
    for (i=0;i<n;i++)
    {
        scanf("%d%d",&a,&b);
        map[a][b]=1;
    }
    dij();
    if(dis[k]>=inf)printf("-1\n");
    else f();
    return 0;
}