算法模板——平衡树Treap

  1 var
  2    i,j,k,l,m,n,head,ts:longint;f1:text;
  3    a,b,fix,lef,rig:array[0..500000] of longint;
  4 procedure lt(var x:longint);inline;
  5           var f,r:longint;
  6           begin
  7                if (x=0) or (rig[x]=0) then exit;
  8                f:=x;r:=rig[x];
  9                b[r]:=b[f];
 10                b[f]:=b[lef[f]]+1+b[LEF[R]];
 11                rig[f]:=lef[r];
 12                lef[r]:=f;
 13                x:=r;
 14           end;
 15 procedure rt(var x:longint);inline;
 16           var f,l:longint;
 17           begin
 18                if (x=0) or (lef[x]=0) then exit;
 19                f:=x;l:=lef[x];
 20                b[l]:=b[f];
 21                b[f]:=b[rig[f]]+1+b[rig[l]];
 22                lef[f]:=rig[l];
 23                rig[l]:=f;
 24                x:=l;
 25           end;
 26 FUNCTION max(x,y:longint):longint;inline;
 27          begin
 28               if x>y then max:=x else max:=y;
 29          end;
 30 function min(x,y:longint):longint;inline;
 31          begin
 32               if x<y then min:=x else min:=y;
 33          end;
 34 procedure ins(var head:longint;x:longint);
 35           begin
 36                if head=0 then
 37                   begin
 38                        head:=x;
 39                        exit;
 40                   end;
 41                if a[x]<a[head] then
 42                   begin
 43                        ins(lef[head],x);
 44                        b[head]:=b[lef[head]]+b[rig[head]]+1;
 45                        if fix[lef[head]]<fix[head] then rt(head);
 46                   end
 47                else
 48                    begin
 49                         ins(rig[head],x);
 50                         b[head]:=b[lef[head]]+b[rig[head]]+1;
 51                         if fix[rig[head]]<fix[head] then lt(head);
 52                    end;
 53           end;
 54 function getp(head,x:longint):longint;
 55          begin
 56               if head=0 then exit(0);
 57               if a[head]=x then exit(head);
 58               if a[head]>x then exit(getp(lef[head],x)) else exit(getp(rig[head],x));
 59          end;
 60 procedure del(var head:longint);
 61           var i,j,k,l,f,r:longint;
 62           begin
 63                if head=0 then exit;
 64                if (lef[head]=0) then
 65                   begin
 66                        b[head]:=b[rig[head]];
 67                        head:=rig[head];
 68                        exit;
 69                   end;
 70                if rig[head]=0 then
 71                   begin
 72                        b[head]:=b[lef[head]];
 73                        head:=lef[head];
 74                        exit;
 75                   end;
 76                if fix[lef[head]]>fix[rig[head]] then
 77                   begin
 78                        lt(head);
 79                        del(lef[head]);
 80                        b[head]:=b[lef[head]]+b[rig[head]]+1;
 81                   end
 82                else
 83                    begin
 84                         rt(head);
 85                         del(rig[head]);
 86                         b[head]:=b[lef[head]]+b[rig[head]]+1;
 87                    end;
 88           end;
 89 procedure det(var head,x:longint);
 90           begin
 91                if head=0 then exit;
 92                if x=head then
 93                   begin
 94                        del(head);
 95                        b[head]:=b[lef[head]]+b[rig[head]]+1;
 96                        exit;
 97                   end;
 98                if lef[head]=x then
 99                   begin
100                        del(lef[head]);
101                        b[head]:=b[lef[head]]+b[rig[head]]+1;
102                        exit;
103                   end;
104                if rig[head]=x then
105                   begin
106                        del(rig[head]);
107                        b[head]:=b[lef[head]]+b[rig[head]]+1;
108                        exit;
109                   end;
110                if a[x]<a[head] then det(lef[head],x) else det(rig[head],x);
111                b[head]:=b[lef[head]]+b[rig[head]]+1;
112           end;
113 procedure showoff(head:longint);
114           begin
115                if head=0 then exit;
116                showoff(lef[head]);
117                write(a[head],' ');
118                showoff(rig[head]);
119           end;
120 function getrank(head,x:longint):longint;
121          var k:longint;
122          begin
123               if head=0 then exit(-1);
124               if x=a[head] then   //亲们注意了，就是这个地方坑了我好久啊啊啊啊啊啊
125                  begin
126                       k:=getrank(lef[head],x);
127                       if k=-1 then exit(b[lef[head]]+1) else exit(k);
128                  end
129               else
130                   begin
131                        if x<a[head] then
132                           begin
133                                exit(getrank(lef[head],x));
134                           end
135                        else
136                            begin
137                                 k:=getrank(rig[head],x);
138                                 if k=-1 then exit(-1) else exit(b[lef[head]]+1+k);
139                            end;
140                   end;
141          end;
142 function rankget(head,x:longint):longint;
143          begin
144               if head=0 then exit(maxlongint);
145               if (b[lef[head]]+1)=x then exit(a[head]);
146               if (b[lef[head]]+1)<x then exit(rankget(rig[head],x-1-b[lef[head]])) else exit(rankget(lef[head],x))
147          end;
148 function getsuc(head,x:longint):longint;
149          begin
150               if (head=0) then exit(+maxlongint);
151               if (a[head]<=x) then exit(getsuc(rig[head],x)) else exit(min(a[head],getsuc(lef[head],x)));
152          end;
153 function getpre(head,x:longint):longint;
154          begin
155               if (head=0) then exit(-maxlongint);
156               if (a[head]>=x) then exit(getpre(lef[head],x)) else exit(max(a[head],getpre(rig[head],x)));
157          end;
158 
159 begin
160      m:=0;head:=0;
161      randomize;
162      readln(n);
163      for i:=1 to  n do
164          begin
165               read(l);
166               case l of
167                    1:begin
168                           readln(j);
169                           inc(m);
170                           a[m]:=j;
171                           fix[m]:=random(maxlongint);
172                           lef[m]:=0;rig[m]:=0;b[m]:=1;
173                           ins(head,m);
174                    end;
175                    2:begin
176                           readln(j);
177                           k:=getp(head,j);
178                           det(head,k);
179                           l:=0;
180                    end;
181                    3:BEGIN
182                           readln(j);
183                           k:=getrank(head,j);
184                           writeln(k);
185                    end;
186                    4:begin
187                           readln(j);
188                           writeln(rankget(head,j));
189                    end;
190                    5:begin
191                           readln(j);
192                           writeln(getpre(head,j));
193                    end;
194                    6:begin
195                           readln(j);
196                           writeln(getsuc(head,j));
197                    end;
198               end;
199 
200               l:=0;
201          end;
202          readln;
203 end.