bzoj2733

好久没写treap，稍微练练
treap的启发式合并

const key=2000007;
var son:array[0..100010,1..2] of longint;
    root,a,b,fa,count,f:array[0..100010] of longint;
    j,n,m,k,x,y,i:longint;
    ch:char;

function getf(x:longint):longint;
  begin
    if f[x]<>x then f[x]:=getf(f[x]);
    exit(f[x]);
  end;

procedure update(x:longint);
  begin
    count[x]:=count[son[x,1]]+count[son[x,2]]+1;
  end;

procedure rotate(x,w:longint);
  var y:longint;
  begin
    y:=fa[x];
    if fa[y]<>0 then
    begin
      if son[fa[y],1]=y then son[fa[y],1]:=x
      else son[fa[y],2]:=x;
    end;
    fa[x]:=fa[y];
    son[y,3-w]:=son[x,w];
    if son[x,w]<>0 then fa[son[x,w]]:=y;
    son[x,w]:=y;
    fa[y]:=x;
    update(y);
    update(x);
  end;

procedure up(i,x:longint);
  var j:longint;
  begin
    j:=fa[i];
    while j<>0 do
    begin
      if b[i]<b[j] then
      begin
        if son[j,1]=i then rotate(i,2)
        else rotate(i,1);
      end
      else break;
      j:=fa[i];
    end;
    if fa[i]=0 then root[x]:=i;
  end;

procedure insert(x,y:longint);
  var p:longint;
  begin
    b[x]:=trunc(random*key)+1;
    count[x]:=1;
    son[x,1]:=0;
    son[x,2]:=0;
    p:=root[y];
    repeat
      inc(count[p]);
      if a[p]>=a[x] then
      begin
        if son[p,1]=0 then break;
        p:=son[p,1];
      end
      else begin
        if son[p,2]=0 then break;
        p:=son[p,2];
      end;
    until false;
    fa[x]:=p;
    if a[p]>=a[x] then son[p,1]:=x else son[p,2]:=x;
    up(x,y);
  end;

procedure succ(x,y:longint);
  begin
    if son[x,1]<>0 then succ(son[x,1],y);
    if son[x,2]<>0 then succ(son[x,2],y);
    insert(x,y);
  end;

procedure union(x,y:longint);
  var k1,k2:longint;
  begin
    k1:=getf(x);
    k2:=getf(y);
    if k1<>k2 then
    begin
      if count[root[k1]]>count[root[k2]] then
      begin
        f[k2]:=k1;
        succ(root[k2],k1);
      end
      else begin
        f[k1]:=k2;
        succ(root[k1],k2);
      end;
    end;
  end;

function find(k,x:longint):longint;
  var p:longint;
  begin
    p:=root[x];
    while p<>0 do
    begin
      if count[son[p,1]]+1=k then exit(p);
      if count[son[p,1]]+1>k then p:=son[p,1]
      else begin
        k:=k-count[son[p,1]]-1;
        p:=son[p,2];
      end;
    end;
    exit(-1);
  end;

begin
  randomize;
  readln(n,k);
  for i:=1 to n do
  begin
    read(a[i]);
    b[i]:=trunc(random*key)+1;
    f[i]:=i;
    root[i]:=i;
  end;
  for i:=1 to k do
  begin
    readln(x,y);
    union(x,y);
  end;
  readln(m);
  for i:=1 to m do
  begin
    readln(ch,x,y);
    if ch='Q' then
    begin
      x:=getf(x);
      writeln(find(y,x));
    end
    else union(x,y);
  end;
end.