B - Por Costel and the Algorithm-最短路记录边

• B - Por Costel and the Algorithm

•  Gym - 100923B 

• #include
  #include
  #include
  #include
  #include
  #include
  using namespace std;
  #define ll long long
  #define maxn 1000005
  #define inf 0x7fffffff
  ll head[maxn],cnt,pre[maxn];
  ll u,v,w,sum,m,n,t;
  bool vis[maxn],out[maxn];
  struct node
  {
      ll v,w,to;
  } edge[maxn];
  struct hed
  {
      ll order,w;
      bool operator<(const hed &x)const
      {
          return w>x.w;
      }
  } top,dis[maxn];
  void ad(ll u,ll v,ll w)
  {
      edge[cnt].v=v;
      edge[cnt].to=head[u];
      edge[cnt].w=w;
      head[u]=cnt;
      cnt++;
  }
  void dijst()
  {
      dis[1].w=0;
      priority_queueq;
      q.push(dis[1]);
      while(!q.empty())
      {
          top=q.top();
          q.pop();
          if(!vis[top.order])
          {
              vis[top.order]=1;
              for(int i=head[top.order]; i!=-1; i=edge[i].to)
              {
                  if(dis[edge[i].v].w>dis[top.order].w+edge[i].w)
                  {
                      dis[edge[i].v].w=dis[top.order].w+edge[i].w;
                      q.push(dis[edge[i].v]);
                      out[i]=1;
                      out[pre[edge[i].v]]=0;
                      pre[edge[i].v]=i;
                  }
              }
          }
      }
  }
  void dfs(ll u)
  {
      for(ll i=head[u]; i!=-1; i=edge[i].to)
      {
          if(out[i])
          {
              sum++;
              if(sum

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