bzoj 1208 HNOI2004宠物收养所 平衡树

裸平衡树，恢复手感用的

//By BLADEVIL
var
    n                       :longint;
    i                       :longint;
    x, y                    :longint;
    t, tot                  :longint;
    key, s, left, right     :array[..] of longint;
    ft                      :longint;
    a, b                    :longint;
    ans                     :longint;

procedure right_rotate(var t:longint);
var
    k                       :longint;
begin
    k:=left[t];
    left[t]:=right[k];
    right[k]:=t;
    s[k]:=s[t];
    s[t]:=s[left[t]]+s[right[t]]+;
    t:=k;
end;

procedure left_rotate(var t:longint);
var
    k                       :longint;
begin
    k:=right[t];
    right[t]:=left[k];
    left[k]:=t;
    s[k]:=s[t];
    s[t]:=s[left[t]]+s[right[t]]+;
    t:=k;
end;

procedure maintain(var t:longint;flag:boolean);
begin
    if not flag then
        if s[left[left[t]]]>s[right[t]] then
            right_rotate(t) else
            if s[right[left[t]]]>s[right[t]] then
            begin
                left_rotate(left[t]);
                right_rotate(t);
            end else exit
    else
        if s[right[right[t]]]>s[left[t]] then
            left_rotate(t) else
            if s[left[right[t]]]>s[left[t]] then
            begin
                right_rotate(right[t]);
                left_rotate(t);
            end else exit;
    maintain(left[t],false);
    maintain(right[t],true);
    maintain(t,true);
    maintain(t,false);
end;

procedure insert(var t:longint; v:longint);
begin
    if t= then
    begin
        inc(tot);
        t:=tot;
        key[t]:=v;
        s[t]:=;
        left[t]:=;
        right[t]:=;
    end else
    begin
        inc(s[t]);
        if v<key[t] then insert(left[t],v) else insert(right[t],v);
        maintain(t,v>=key[t]);
    end;
end;

function delete(var t:longint; v:longint):longint;
begin
    dec(s[t]);
    if (v=key[t]) or (v<key[t]) and (left[t]=) or (v>key[t]) and (right[t]=) then
    begin
        delete:=key[t];
        if (left[t]=) or (right[t]=) then
            t:=left[t]+right[t] else
            key[t]:=delete(left[t],key[t]+);
    end else
        if v<key[t] then delete:=delete(left[t],v) else delete:=delete(right[t],v);
end;

function pre(var t:longint; v:longint):longint;
begin
    if t= then exit(-);
    if v<key[t] then pre:=pre(left[t],v) else
    begin
        pre:=pre(right[t],v);
        if pre=- then pre:=key[t];
    end;
end;

function succ(var t:longint; v:longint):longint;
begin
    if t= then exit(-);
    if key[t]<=v then succ:=succ(right[t],v) else
    begin
        succ:=succ(left[t],v);
        if succ=- then succ:=key[t];
    end;
end;

begin
    read(n);
    ans:=;
    t:=; tot:=; s[t]:=;

    for i:= to n do
    begin
        read(x,y);
        if x=ft then insert(t,y) else
            if s[t]= then
            begin
                ft:=x;
                insert(t,y);
            end else
            begin
                a:=pre(t,y); b:=succ(t,y);
                if a=- then a:=-maxlongint div ;
                if b=- then b:=maxlongint div ;
                if abs(b-y)<abs(y-a) then
                begin
                    ans:=(ans+abs(b-y)) mod ;
                    b:=delete(t,b);
                end else
                begin
                    ans:=(ans+abs(y-a)) mod ;
                    a:=delete(t,a);
                end;
            end;
    end;
    writeln(ans);

end.