目标：在两个半月内基本掌握相关基本查询，以及Splay、SBT、Trie这三种特殊树的形式。

千里之行，始于足下。

一段非常普通的bst

 1 program bst;
 2 
 3 Type
 4  node=^rec;
 5  rec=record
 6    lch,rch:node;
 7    d,pos:longint;
 8  end;
 9 
10 Var
11  h,u:node;
12  i,o,n:longint;
13 Procedure init(var p:node;k,po:longint);
14   begin
15   p^.lch:=nil;
16   p^.rch:=nil;
17   p^.d:=k;
18   p^.pos:=po;
19 end;
20 
21 Procedure ins(var p:node;q,po:longint);
22 var
23  p1:node;
24   begin
25   if p=nil then
26     begin
27     new(p);
28     init(p,q,po);
29     exit;
30   end;
31   if q<=p^.d then ins(p^.lch,q,po) else ins(p^.rch,q,po);
32 end;
33 
34 Function find(p:node;q:longint):node;
35   begin
36   if p=nil then exit(nil);
37   if p^.d=q then exit(p);
38   if q<=p^.d then exit(find(p^.lch,q)) else
39     exit(find(p^.rch,q));
40 end;
41 
42 Procedure delete(var p:node);
43 var
44  t,s,q:node;
45   begin
46   if p^.lch=nil then
47     begin
48     q:=p;
49     p:=p^.rch;
50     dispose(q);
51   end else
52   if p^.rch=nil then
53     begin
54     q:=p;
55     p:=p^.lch;
56     dispose(q);
57   end else
58     begin
59     t:=p;
60     s:=p^.lch;
61     while s^.rch<>nil do
62       begin
63       t:=s;
64       s:=s^.rch;
65     end;
66     p^.d:=s^.d;
67     p^.pos:=s^.pos;
68     if t<>p then
69       t^.rch:=s^.lch
70     else
71       t^.lch:=s^.lch;
72     dispose(s);
73   end;
74 end;
75 
76 Procedure delBST(var p:node;q:longint);
77   begin
78   if p=nil then exit;
79   if p^.d=q then delete(p) else
80   if q<p^.d then delbst(p^.lch,q) else
81   delbst(p^.rch,q);
82 end;
83 
84   begin
85   readln(n);
86   for i:=1 to n do
87     begin
88     readln(o);
89     ins(h,o,i);
90   end;
91   delbst(h,5);
92   while true do
93     begin
94     readln(o);
95     if find(h,o)=nil then writeln('Not found!') else writeln(find(h,o)^.pos);
96   end;
97 end.