[BZOJ3224] Tyvj 1728 普通平衡树

传送门

http://www.lydsy.com/JudgeOnline/problem.php?id=3224

题目大意

支持以下操作
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)

题解

平衡树模板题

const    maxn=100005;var    w:array[-1..maxn,1..6]of longint;    i,j,k:longint;    n,sum,root,a,b:longint;procedure print(a:longint);var i:longint;begin    if w[a,1]<>-1 then print(w[a,1]);    for i:=1 to w[a,5] do write(w[a,6],' ');    if w[a,2]<>-1 then print(w[a,2]);    if a=root then writeln;end;procedure rotate(a,kind:longint);var b,unkind:longint;begin    b:=w[a,3]; unkind:=kind xor 3;    w[a,4]:=w[b,4]; dec(w[b,4],w[a,5]+w[w[a,kind],4]);    w[b,kind]:=w[a,unkind];    w[w[a,unkind],3]:=b;    w[a,unkind]:=b;    w[a,3]:=w[b,3];    w[b,3]:=a;    if w[a,3]<>-1    then        if w[w[a,3],1]=b        then w[w[a,3],1]:=a        else w[w[a,3],2]:=a;end;procedure splay(a,goal:longint);var b,kind,unkind:longint;begin    while w[a,3]<>goal do        begin            b:=w[a,3];            if w[b,1]=a then kind:=1 else kind:=2; unkind:=kind xor 3;            if w[b,3]=goal then rotate(a,kind)            else                if w[w[b,3],kind]=b                then begin rotate(b,kind); rotate(a,kind); end                else begin rotate(a,kind); rotate(a,unkind); end;        end;    if goal=-1 then root:=a;end;procedure init(a:longint);var tt,fa,kind:longint;begin    tt:=root;    while tt<>-1 do        begin            inc(w[tt,4]);            if w[tt,6]=a then break;            fa:=tt;            if a<w[tt,6]            then begin kind:=1; tt:=w[tt,1]; end            else begin kind:=2; tt:=w[tt,2]; end;        end;    if w[tt,6]=a    then inc(w[tt,5])    else begin inc(sum); w[sum,1]:=-1; w[sum,2]:=-1; w[sum,3]:=fa; w[sum,4]:=1; w[sum,5]:=1; w[sum,6]:=a; w[fa,kind]:=sum; tt:=sum; end;    splay(tt,-1);end;function getmax(a:longint):longint;var tt:longint;begin    tt:=a;    while w[tt,2]<>-1 do        tt:=w[tt,2];    exit(tt);end;function getmin(a:longint):longint;var tt:longint;begin    tt:=a;    while w[tt,1]<>-1 do        tt:=w[tt,1];    exit(tt);end;procedure del(a:longint);var tt:longint;begin    tt:=root;    while w[tt,6]<>a do        if a<w[tt,6]        then tt:=w[tt,1]        else tt:=w[tt,2];    splay(tt,-1);    if w[root,5]=1    then         begin            splay(getmax(w[root,1]),root);            w[w[root,1],2]:=w[root,2]; w[w[root,1],4]:=w[root,4]-1; root:=w[root,1]; w[w[root,2],3]:=root; w[root,3]:=-1;        end    else         begin dec(w[root,5]); dec(w[root,4]); end;end;function getrank(a:longint):longint;var tt:longint;begin    tt:=root;    while w[tt,6]<>a do        if a<w[tt,6]        then tt:=w[tt,1]        else tt:=w[tt,2];    splay(tt,-1);    exit(w[w[tt,1],4]);end;function getkth(a:longint):longint;var tt:longint;begin    tt:=root;    while (a<=w[w[tt,1],4])or(a>w[w[tt,1],4]+w[tt,5]) do        if a<=w[w[tt,1],4]        then tt:=w[tt,1]        else begin dec(a,w[w[tt,1],4]+w[tt,5]); tt:=w[tt,2]; end;       exit(w[tt,6]);end;begin    readln(n); sum:=2; root:=2;    w[1,1]:=-1; w[1,2]:=-1; w[1,3]:=2; w[1,4]:=1; w[1,5]:=1; w[1,6]:=-1000000005;    w[2,1]:=1; w[2,2]:=-1; w[2,3]:=-1; w[2,4]:=2; w[2,5]:=1; w[2,6]:=1000000005;    for i:=1 to n do        begin            readln(a,b);            case a of            1:begin init(b); end;            2:begin del(b); end;            3:begin writeln(getrank(b)); end;            4:begin writeln(getkth(b+1)); end;            5:begin init(b); writeln(w[getmax(w[root,1]),6]); del(b); end;            6:begin init(b); writeln(w[getmin(w[root,2]),6]); del(b); end;            end;    end;end.