hdu 1535 Invitation Cards

hdu 1535 Invitation Cards

#include
#include
#include
#include
using namespace std;
const int inf=1<<24;
const int N=1000000+5;

struct node
{
    int to,w;
    node* next;
};
node* edge[N];
node* reedge[N];
int n,m,x,dist[N],inq[N],q[N];

void spfa(int flag)
{
    int i,u,h=0,t=1;
    node* ptr;
    for(i=0; i<=n; i++)
    {
        dist[i]=inf;
        inq[i]=0;
    }
    dist[1]=0;
    inq[1]=1;
    q[0]=1;
    while(h!=t)
    {
        u=q[h];
        h++;
        inq[u]=0;
        if(flag==1) ptr=edge[u];
        else ptr=reedge[u];
        while(ptr)
        {
            if(dist[ptr->to]>(dist[u]+ptr->w))
            {
                dist[ptr->to]=dist[u]+ptr->w;
                if(inq[ptr->to]==0)
                {
                    q[t]=ptr->to;
                    t++;
                    inq[ptr->to]=1;
                }
            }
            ptr=ptr->next;
        }

    }
}

int main()
{
    int cas,i,u,v,w,ans;
    scanf("%d",&cas);
    while(cas--)
    {
        scanf("%d%d",&n,&m);
        for(i=1; i<=n; i++)
        {
            edge[i]=NULL;
            reedge[i]=NULL;
        }
        for(i=0; ito=u;
            temp->w=w;
            temp->next=NULL;
            if(edge[v]==NULL)
            {
                edge[v]=temp;
            }
            else
            {
                temp->next=edge[v];
                edge[v]=temp;
            }

            temp= new node;
            temp->to=v;
            temp->w=w;
            temp->next=NULL;
            if(reedge[u]==NULL)
            {
                reedge[u]=temp;
            }
            else
            {
                temp->next=reedge[u];
                reedge[u]=temp;
            }
        }
        ans=0;
        spfa(1);
        for(i=2; i<=n; i++)
        {
            //printf("%d\n",dist[i]);
            ans+=dist[i];
        }
        spfa(0);
        for(i=2; i<=n; i++)
        {
            ans+=dist[i];
        }
        printf("%d\n",ans);
    }
    return 0;
}