实现功能如下——1. 插入x数
2. 删除x数(若有多个相同的数，因只删除一个)
3. 查询x数的排名(若有多个相同的数，因输出最小的排名)
4. 查询排名为x的数
5. 求x的前驱(前驱定义为小于x，且最大的数)
6. 求x的后继(后继定义为大于x，且最小的数)
本程序的实现原理为Treap平衡树
详见BZOJ3224
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.