NOIP2015BLOCKADE c++ 代码

 #include<algorithm>
 #include<fstream>
 #include<functional>
 #include<iostream>
 using namespace std;
 static const int N=;
 typedef long long int64;
 struct node
 {
     int v,w;
     node *next;
 }alist[*N];
 struct heapnode
 {
     int64 w;
     int u;
     bool operator>(const heapnode &r)const
     {
         return w>r.w;
     }
 };
 int p[N][];
 int64 w[N][];
 void dfs1(int u)
 {
     for(node *i=alist[u].next;i;i=i->next)
         if(i->v!=p[u][])
         {
             p[i->v][]=u;
             w[i->v][]=i->w;
             dfs1(i->v);
         }
 }
 bool visit[N];
 void dfs2(int u)
 {
     if(visit[u])return;
     if(!alist[u].next->next)return;
     visit[u]=true;
     for(node *i=alist[u].next;i;i=i->next)
         if(i->v!=p[u][])
         {
             dfs2(i->v);
             if(!visit[i->v])
             {
                 visit[u]=false;
                 break;
             }
         }
 }
 int main()
 {
     ifstream fin("blockade.in");
     ofstream fout("blockade.out");
     int n(),m();
     fin>>n;
     node *anode(alist+n+);
     for(int i=;i<n-;i++)
     {
         int u(),v(),ww();
         fin>>u>>v>>ww;
         anode->v=v;
         anode->w=ww;
         anode->next=alist[u].next;
         alist[u].next=anode++;
         anode->v=u;
         anode->w=ww;
         anode->next=alist[v].next;
         alist[v].next=anode++;
     }
     fin>>m;
     static int d[N];
     for(int i=;i<m;i++)
         fin>>d[i];
     int NScount=;
     for(node *i=alist[].next;i;i=i->next)
     {
         NScount++;
         p[i->v][]=;
         w[i->v][]=i->w;
         dfs1(i->v);
     }
     if(NScount>m)
     {
         fout<<"-1"<<endl;
         return ;
     }
     for(int j=;j<=;j++)
         for(int i=;i<=n;i++)
         {
             p[i][j]=p[p[i][j-]][j-];
             w[i][j]=w[i][j-]+w[p[i][j-]][j-];
         }
     static heapnode a[N],b[N];
     heapnode *atop(),*aback(),*btop(),*bback();
     static int _w[N];
     for(node *i=alist[].next;i;i=i->next)
         _w[i->v]=i->w;
     int64 l(),r(1e16),ans(1e16);
     greater<heapnode> comp;
     while(l<=r)
     {
         atop=a;
         aback=a;
         btop=b;
         bback=b;
         int64 mm=(l+r)>>;
         for(int i=;i<=n;i++)
             visit[i]=false;
         for(int i=;i<m;i++)
         {
             int u=d[i];
             int64 ww=mm;
             for(int j=;j>=;j--)
                 if(p[u][j]&&p[u][j]!=&&ww>=w[u][j])
                 {
                     ww-=w[u][j];
                     u=p[u][j];
                 }
             if(/*p[u][0]==1&&*/ww>w[u][])
             {
                 aback->w=ww-w[u][];
                 aback->u=u;
                 aback++;
                 push_heap(atop,aback,comp);
             }
             else visit[u]=true;
         }
         dfs2();
         if(visit[])
         {
             ans=mm;
             r=mm-;
         }
         else
         {
             for(node *i=alist[].next;i;i=i->next)
                 if(!visit[i->v])
                 {
                     bback->w=i->w;
                     bback->u=i->v;
                     bback++;
                     push_heap(btop,bback,comp);
                 }
             while(btop!=bback||atop!=aback)
             {
                 while(atop!=aback&&!visit[atop->u]&&atop->w<_w[atop->u])
                 {
                     visit[atop->u]=true;
                     pop_heap(atop,aback,comp);
                     aback--;
                 }
                 while(btop!=bback&&visit[btop->u])
                 {
                     pop_heap(btop,bback,comp);
                     bback--;
                 }
                 if(btop==bback||atop==aback)break;
                 if(atop->w>=btop->w)
                 {
                     visit[btop->u]=true;
                     pop_heap(atop,aback,comp);
                     aback--;
                     pop_heap(btop,bback,comp);
                     bback--;
                 }
                 else
                 {
                     pop_heap(atop,aback,comp);
                     aback--;
                 }
             }
             if(btop==bback)
             {
                 ans=min(ans,mm);
                 r=mm-;
             }
             else l=mm+;
         }
     }
     fout<<ans<<endl;
     return ;
 }