Luogu P1113 Chores "topological sort" by cellur925

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This problem we know is a topological sort, however, in how to transform the problem took a lot of work, one hours after the last still helpless to see the QWQ.

Obviously we can get a DAG for each task, from his leading task to the one where he even has a side. The topology is sorted on this DAG, and the cost of updating to the task J is Max (F[j],f[i]+val[j]). When we find a point with a degree of 0, we can use it to update the final answer.

Code

1#include <cstdio>2#include <algorithm>3#include <queue>4 5 using namespacestd;6 7 intn,ans,tot,cnt;8 intval[10090],du[10090],head[10090],f[10090],cdu[10090];9 structnode{Ten     intnext,to; One}edge[200900]; A  - voidAddintXinty) - { theedge[++tot].next=Head[x]; -head[x]=tot; -edge[tot].to=y; - } +  - voidtopo () + { Aqueue<int>Q; at      for(intI=1; i<=n;i++) -         if(du[i]==0) Q.push (i), f[i]=Val[i]; -      while(!q.empty ()) -     { -         intx=Q.front (); Q.pop (); -          for(intI=head[x];i;i=edge[i].next) in         { -             inty=edge[i].to; toF[y]=max (f[y],f[x]+val[y]); +             if(--du[y]==0) -             { the                 if(!cdu[y]) ans=Max (ans,f[y]); *                 ElseQ.push (y); $             }Panax Notoginseng         } -     } the } +  A intMain () the { +scanf"%d",&n); -      for(intI=1; i<=n;i++) $     { $         intopt=0, y=0; -scanf"%d%d",&opt,&val[i]); -          while(SCANF ("%d", &y) &&y!=0) Add (opt,y), du[y]++,cdu[opt]++; the     } - topo ();Wuyiprintf"%d", ans); the     return 0; -}

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Details: The size of the open array is very fastidious, the size of the adjacency table is not control, began to re a point.

Luogu P1113 Chores "topological sort" by cellur925