【BZOJ1103】大都市meg（DFS序，树状数组）

 1 var head,vet,next,a,b,c,t,flag:array[1..1000000]of longint;
 2     n,m,tot,i,x,y,time,j,k:longint;
 3     ch:string;
 4 
 5 procedure add(a,b:longint);
 6 begin
 7  inc(tot);
 8  next[tot]:=head[a];
 9  vet[tot]:=b;
10  head[a]:=tot;
11 end;
12 
13 procedure dfs(u:longint);
14 var e,v:longint;
15 begin
16  flag[u]:=1; inc(time); a[time]:=u; b[u]:=time;
17  e:=head[u];
18  while e<>0 do
19  begin
20   v:=vet[e];
21   if flag[v]=0 then dfs(v);
22   e:=next[e];
23  end;
24  inc(time); a[time]:=u; c[u]:=time;
25 end;
26 
27 function lowbit(x:longint):longint;
28 begin
29  exit(x and (-x));
30 end;
31 
32 function sum(x:longint):longint;
33 begin
34  sum:=0;
35  while x>0 do
36  begin
37   sum:=sum+t[x];
38   x:=x-lowbit(x);
39  end;
40 end;
41 
42 procedure update(x,y:longint);
43 begin
44  while x<=n<<1 do
45  begin
46   t[x]:=t[x]+y;
47   x:=x+lowbit(x);
48  end;
49 end;
50 
51 begin
52  assign(input,‘bzoj1103.in‘); reset(input);
53  assign(output,‘bzoj1103.out‘); rewrite(output);
54  readln(n);
55  for i:=1 to n-1 do
56  begin
57   readln(x,y);
58   add(x,y);
59   add(y,x);
60  end;
61  dfs(1);
62  for i:=1 to n do
63  begin
64   update(b[i],1);
65   update(c[i],-1);
66  end;
67  readln(m);
68  for i:=1 to n+m-1 do
69  begin
70   readln(ch); x:=0; y:=0;
71   if ch[1]=‘W‘ then
72   begin
73    for j:=3 to length(ch) do x:=x*10+ord(ch[j])-ord(‘0‘);
74    writeln(sum(b[x])-1);
75   end;
76   if ch[1]=‘A‘ then
77   begin
78    for j:=3 to length(ch) do
79    begin
80     if ch[j]=‘ ‘ then break;
81     x:=x*10+ord(ch[j])-ord(‘0‘);
82    end;
83    k:=j;
84    for j:=k+1 to length(ch) do y:=y*10+ord(ch[j])-ord(‘0‘);
85    update(b[y],-1);
86    update(c[y],1);
87   end;
88  end;
89  close(input);
90  close(output);
91 end.