BZOJ 1922: [Sdoi2010]大陆争霸 Dijkstra

Code:

#include <queue>
#include <vector>
#include <cstdio>
#include <cstring>
#include <algorithm>
#define N 3004
#define M 70004
#define ll long long
#define setIO(s) freopen(s".in","r",stdin)
using namespace std;
int edges,n,m;
vector<int>G[N];
ll arrive[N],into[N],d[N];
int hd[N],to[M<<1],nex[M<<1],val[M<<1],deg[N],done[N];
void addedge(int u,int v,int c)
{
    nex[++edges]=hd[u],hd[u]=edges,to[edges]=v,val[edges]=c;
}
struct Node
{
    int u;
    ll dis;
    Node(int u=0,ll dis=0):u(u),dis(dis){}
    bool operator<(Node b) const
    {
        return b.dis<dis;
    }
};
priority_queue<Node>q;
void Dijkstra()
{
    int s = 1;
    memset(d,0x3f,sizeof(d));
    memset(arrive,0x3f,sizeof(arrive));
    d[s]=arrive[s]=into[s]=deg[s]=0, q.push(Node(s,0));
    for(;!q.empty();)
    {
        Node e=q.top(); q.pop();
        int u=e.u;
        if(done[u]) continue;
        done[u]=1;
        for(int i=hd[u];i;i=nex[i])
        {
            int v=to[i];
            if(arrive[v]>d[u]+val[i])
            {
                arrive[v]=d[u]+val[i];
                if(deg[v]==0)
                {
                    d[v]=max(into[v], arrive[v]);
                    q.push(Node(v, d[v]));
                }
            }
        }
        for(int i=0;i<G[u].size();++i)
        {
            int v=G[u][i];
            --deg[v];
            into[v]=max(into[v], d[u]);
            if(deg[v]==0)
            {
                d[v]=max(into[v], arrive[v]);
                q.push(Node(v, d[v]));
            }
        }
    }
}
int main()
{
    int i,j;
    // setIO("input");
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;++i)
    {
        int a,b,c;
        scanf("%d%d%d",&a,&b,&c),addedge(a,b,c);
    }
    for(i=1;i<=n;++i)
    {
        int t,k;
        scanf("%d",&t);
        for(j=1;j<=t;++j)
        {
            ++deg[i],scanf("%d",&k),G[k].push_back(i);
        }
    }
    Dijkstra();
    printf("%lld\n",d[n]);
    return 0;
}