算法模板——平衡树Treap 2
实现功能：同平衡树Treap 1（BZOJ3224 / tyvj1728）
这次的模板有了不少的改进，显然更加美观了，几乎每个部分都有了不少简化，尤其是删除部分，这个参照了hzwer神犇的写法，在此鸣谢，然后，贴模板走人
1 var 2 i,j,k,l,m,n,head,tot:longint; 3 a,b,lef,rig,fix:array[0..100010] of longint; 4 function min(x,y:longint):longint; 5 begin 6 if x<y then min:=x else min:=y; 7 end; 8 function max(x,y:longint):longint; 9 begin 10 if x>y then max:=x else max:=y; 11 end; 12 procedure lt(var x:longint); 13 var f,r:longint; 14 begin 15 if (x=0) or (rig[x]=0) then exit; 16 b[rig[x]]:=b[x];b[x]:=b[lef[x]]+b[lef[rig[x]]]+1; 17 f:=x;r:=rig[x]; 18 rig[f]:=lef[r]; 19 lef[r]:=f; 20 x:=r; 21 end; 22 procedure rt(var x:longint); 23 var f,l:longint; 24 begin 25 if (x=0) or (lef[x]=0) then exit; 26 b[lef[x]]:=b[x];b[x]:=b[rig[x]]+b[rig[lef[x]]]+1; 27 f:=x;l:=lef[x]; 28 lef[f]:=rig[l]; 29 rig[l]:=f; 30 x:=l; 31 end; 32 function newp(x:longint):longint; 33 begin 34 inc(tot);newp:=tot; 35 a[tot]:=x;b[tot]:=1; 36 lef[tot]:=0;rig[tot]:=0; 37 fix[tot]:=random(maxlongint); 38 end; 39 procedure ins(var x:longint;y:longint); 40 begin 41 if x=0 then 42 begin 43 x:=newp(y); 44 exit; 45 end; 46 if y<a[x] then 47 begin 48 ins(lef[x],y);b[x]:=b[lef[x]]+b[rig[x]]+1; 49 if fix[lef[x]]<fix[x] then rt(x); 50 end 51 else 52 begin 53 ins(rig[x],y);b[x]:=b[lef[x]]+b[rig[x]]+1; 54 if fix[rig[x]]<fix[x] then lt(x); 55 end; 56 end; 57 procedure del(var x:longint;y:longint); 58 begin 59 if x=0 then exit; 60 if a[x]=y then 61 begin 62 if lef[x]=0 then x:=rig[x] else 63 if rig[x]=0 then x:=lef[x] else 64 if fix[lef[x]]>fix[rig[x]] then 65 begin 66 lt(x);del(lef[x],y); 67 b[x]:=b[lef[x]]+b[rig[x]]+1; 68 end 69 else 70 begin 71 rt(x);del(rig[x],y); 72 b[x]:=b[lef[x]]+b[rig[x]]+1; 73 end; 74 end 75 else if y<a[x] then 76 begin 77 del(lef[x],y); 78 b[x]:=b[lef[x]]+b[rig[x]]+1; 79 end 80 else begin 81 del(rig[x],y); 82 b[x]:=b[lef[x]]+b[rig[x]]+1; 83 end; 84 end; 85 function getrank(x,y:longint):longint; 86 begin 87 if x=0 then exit(0); 88 if y>a[x] then exit(b[lef[x]]+1+getrank(rig[x],y)) else exit(getrank(lef[x],y)); 89 end; 90 function rankget(x,y:longint):longint; 91 begin 92 if y=(b[lef[x]]+1) then exit(a[x]); 93 if y<(b[lef[x]]+1) then exit(rankget(lef[x],y)) else exit(rankget(rig[x],y-1-b[lef[x]])); 94 end; 95 function getpre(x,y:longint):longint; 96 begin 97 if x=0 then exit(-maxlongint); 98 if a[x]<y then exit(max(a[x],getpre(rig[x],y))) else exit(getpre(lef[x],y)); 99 end; 100 function getsuc(x,y:longint):longint; 101 begin 102 if x=0 then exit(maxlongint); 103 if a[x]>y then exit(min(a[x],getsuc(lef[x],y))) else exit(getsuc(rig[x],y)); 104 end; 105 begin 106 readln(n);tot:=0;head:=0; 107 for i:=1 to n do 108 begin 109 readln(j,k); 110 case j of 111 1:ins(head,k); 112 2:del(head,k); 113 3:writeln(getrank(head,k)+1); 114 4:writeln(rankget(head,k)); 115 5:writeln(getpre(head,k)); 116 6:writeln(getsuc(head,k)); 117 end; 118 end; 119 end.
