算法模板——splay区间反转 1

实现的功能：将序列区间反转，并维护

详见BZOJ3223

 var
    i,j,k,l,m,n,head,a1,a2:longint;
    s1:ansistring;
    a,b,c,d,fat,lef,rig:array[..] of longint;
 procedure swap(var x,y:longint);inline;
           var z:longint;
           begin
                z:=x;x:=y;y:=z;
           end;
 
 procedure ext(x:longint);inline;
           begin
                if (x=) then exit;
                if c[x]= then exit;
                swap(lef[x],rig[x]);
                c[x]:=;
                c[lef[x]]:=-c[lef[x]];
                c[rig[x]]:=-c[rig[x]];
                c[]:=;
           end;
 procedure rt(x:longint);inline;
           var f,l:longint;
           begin
                if x= then exit;
                ext(x);
                if lef[x]= then exit;
                ext(lef[x]);
                f:=x;l:=lef[x];
                b[lef[x]]:=b[x];
                b[x]:=b[rig[x]]++b[rig[l]];
                lef[x]:=rig[l];
                fat[rig[l]]:=x;
                rig[l]:=x;
                fat[l]:=fat[x];
                fat[x]:=l;
                if rig[fat[l]]=x then rig[fat[l]]:=l;
                if lef[fat[l]]=x then lef[fat[l]]:=l;
                fat[]:=;
           end;
 procedure lt(x:longint);inline;
           var f,r:longint;
           begin
                if x= then exit;
                ext(x);if rig[x]= then exit;
                ext(rig[x]);
                f:=x;r:=rig[x];
                b[rig[x]]:=b[x];
                b[x]:=+b[lef[x]]+b[lef[r]];
                rig[x]:=lef[r];
                fat[lef[r]]:=x;
                lef[r]:=x;
                fat[r]:=fat[x];
                fat[x]:=r;
                if rig[fat[r]]=x then rig[fat[r]]:=r;
                if lef[fat[r]]=x then lef[fat[r]]:=r;
                fat[]:=;
           end;
 procedure ins(x,y:longint);inline;
           begin
                if a[y]<a[x] then
                   begin
                        if lef[x]= then
                           begin
                                lef[x]:=y;
                                fat[y]:=x;
                           end
                        else ins(lef[x],y);
                   end
                else
                    begin
                         if rig[x]= then
                            begin
                                 rig[x]:=y;
                                 fat[y]:=x;
                            end
                         else ins(rig[x],y);
                    end;
                b[x]:=+b[lef[x]]+b[rig[x]];
           end;
 procedure up2(var x:longint);inline;
           begin
                if (fat[x]=) or (x=) then exit;
                if lef[fat[x]]=x then
                   begin
                        if lef[fat[fat[x]]]=fat[x] then
                           begin
                                rt(fat[fat[x]]);
                                rt(fat[x]);
                           end
                        else
                            begin
                                 rt(fat[x]);
                                 lt(fat[x]);
                            end;
                   end
                else
                    begin
                         if rig[fat[fat[x]]]=fat[x] then
                            begin
                                 lt(fat[fat[x]]);
                                 lt(fat[x]);
                            end
                         else
                             begin
                                  lt(fat[x]);
                                  rt(fat[x]);
                             end;
                    end;
           end;
 procedure up1(x:longint);inline;
           begin
                if (x=) or (fat[x]=) then exit;
                if lef[fat[x]]=x then rt(fat[x]) else lt(fat[x]);
           end;
 procedure splay(x:longint);inline;
           begin
                if (x=) or (fat[x]=) then exit;
                while fat[fat[x]]> do
                      up2(x);
                if fat[x]> then up2(x);
                head:=x;
           end;
 procedure splay2(x:longint);inline;
           begin
                if (x=) or (fat[x]=) then exit;
                while fat[fat[fat[x]]]> do
                      up2(x);
                if fat[fat[x]]> then up1(x);
           end;
 function getrank(x,y:longint):longint;inline;
          begin
               if (x=) then exit();
               ext(x);
               if (b[lef[x]]+)=y then exit(x);
               if (b[lef[x]]+)>y then exit(getrank(lef[x],y)) else exit(getrank(rig[x],y--b[lef[x]]));
          end;
 procedure turn(x,y:longint);inline;
           var a1,a2:longint;
           begin
                if (x=) and (y=n) then
                   c[head]:=-c[head]
                else
                    begin
                         if (x=) then
                            begin
                                 a1:=getrank(head,y+);
                                 splay(a1);
                                 ext(a1);
                                 c[lef[a1]]:=-c[lef[a1]];
                            end
                         else
                             begin
                                  if (y=n) then
                                     begin
                                          a2:=getrank(head,x-);
                                          splay(a2);
                                          ext(a2);
                                          c[rig[a2]]:=-c[rig[a2]];
                                     end
                                  else
                                      begin
                                           a1:=getrank(head,x-);
                                           a2:=getrank(head,y+);
                                           splay(a2);splay2(a1);
                                           ext(a2);ext(a1);
                                           c[rig[a1]]:=-c[rig[a1]];
                                      end;
                             end;
                    end;
           end;
 function showoff(x:longint):ansistring;inline;
          var s1:ansistring;
          begin
               if x= then exit('');
               ext(x);
               str(x,s1);
               exit(showoff(lef[x])+s1+' '+showoff(rig[x]));
          end;
 begin
      readln(n,m);
      for i:= to n do
          begin
               a[i]:=i;c[i]:=;b[i]:=;
          end;
      head:=;
      for i:= to n do
          begin
               ins(head,i);
               splay(random(i)+);
          end;
      for i:= to m do
          begin
               readln(a1,a2);
               turn(a1,a2);
          end;
      s1:=showoff(head);
      writeln(s1);
      readln;
 end.