"Distance gdkoi:44 days &gdoi:107 days" "BZOJ1040" [ZJOI2008] Knight

In fact, is ready to retire, but Gdoi will continue to learn before!! As an interest in learning, has lost confidence in the competition, I still go back to kneel down the Culture class bar Qaq

First ring set of tree DP ... In fact, the idea is very simple, the ring apart, classified processing. If the two points opened are u,v,dp[i,0..1] respectively, the knight is not selected and selected

(1) Do not choose U,v Point Random (2) u random, V-point not selected ...

Classified DP processing can be

1 Constmaxn=1000419;2 type3Edgetype=Record4 Toward,next:longint;5  End;6 7 var8EdgeArray[0.. maxn*2] ofEdgetype;9FirstArray[0.. MAXN] ofLongint;TenValArray[0.. MAXN] ofInt64; OneDp:Array[0.. MAXN,0..1] ofInt64; APD,VB,VC:Array[0.. MAXN] ofBoolean; - Root,vv,e,tot:longint; - N:longint; the functionMax (X,y:int64): Int64;begin ifX>y ThenExit (x)ElseExit (y);End; -  - procedureAddedge (i,j:longint); - begin +edge[tot].toward:=J; -edge[tot].next:=First[i]; +first[i]:=tot; A Inc (TOT); at End; -  - procedureAdd (i,j:longint); - begin - Addedge (I,J); Addedge (j,i); - End; in  - procedureDFS (v,fa:longint); to varI,tmp:longint; + begin -pd[v]:=true; thei:=First[v]; *   whilei<>-1  Do $   beginPanax Notoginsengtmp:=Edge[i].toward; -    if  notPD[TMP] Thendfs (TMP,V) the     Else ifTmp<>fa Then +      begin Avv:=v; theroot:=tmp; +e:=i; -      End; $i:=Edge[i].next; $   End; - End; -  the procedureDPB (V:longint); //ban U - varI,tmp:longint;Wuyi begin theDp[v,0]:=0; Dp[v,1]:=VAL[V]; vb[v]:=true; -i:=First[v]; Wu   whilei<>-1  Do -   begin Abouttmp:=Edge[i].toward; $    if(i<>e) and(I XOR1&LT;&GT;E) and  notVB[TMP] Then -     begin - DPB (TMP); -Dp[v,0]:=dp[v,0]+max (Dp[tmp,0],dp[tmp,1]); ADp[v,1]:=dp[v,1]+dp[tmp,0]; +     End; thei:=Edge[i].next; -   End; $ End; the  the procedureDPC (V:longint); //ban V; the varI,tmp:longint; the begin -Dp[v,0]:=0; Dp[v,1]:=VAL[V]; vc[v]:=true; ini:=First[v]; the   whilei<>-1  Do the   begin Abouttmp:=Edge[i].toward; the    if(i<>e) and(I XOR1&LT;&GT;E) and  notVC[TMP] Then the     begin the DPC (TMP); +Dp[v,1]:=dp[v,1]+dp[tmp,0]; -      ifTmp=vv ThenDp[v,0]:=dp[v,0]+dp[tmp,0] the       ElseDp[v,0]:=dp[v,0]+max (Dp[tmp,0],dp[tmp,1]);Bayi     End; thei:=Edge[i].next; the   End; - End; -  the proceduresolve; the varI:longint; the Rec,ans:int64; the begin -ans:=0; the   fori:=1  toN Do the   if  notPd[i] Then the    begin94rec:=0; root:=-1; DFS (i,-1); theDPB (root); Rec:=dp[root,0]; theDPC (root); Rec:=max (Rec,max (Dp[root,0],dp[root,1])); the Inc (ANS,REC);98    End; About writeln (ans); - End;101 102 procedureInit;103 varI,x:longint;104 begin theFillchar (first,sizeof (first),255);106 READLN (n);107tot:=0;108   fori:=1  toN Do109   begin the readln (val[i],x);111 Add (i,x); the   End;113 End; the  the Begin the Init;117 solve;118End.

"Distance gdkoi:44 days &gdoi:107 days" "BZOJ1040" [ZJOI2008] Knight