1036: [ZJOI2008]树的统计Count (树链剖分模板)

var
  next,e:array[0..700000]of longint;
  a,l,r,b:Array[0..150000]of longint;
  aa,son,d,head,top,point,fa,size,w:array[0..300000]of longint;
  pp,qq,opt,ll,rr,ansa,ansb,root,uu,vv,i,j,n,ee,xx:longint;
  v:array[0..300000]of boolean;
  ch,ch1:char;
function max(aa,bb:longint):longint;
  begin
  if (aa>bb) then exit(aa)
  else exit(bb);
  end;
procedure swap(var aaa,bbb:longint);
  var tt:longint;
  begin
  tt:=aaa;aaa:=bbb;bbb:=tt;
  end;
procedure dfs1(u:longint);
  var j:longint;
  begin
  j:=head[u];
  size[u]:=1;
  while j<>0 do
    begin
    if d[e[j]]=0 then
      begin
      d[e[j]]:=d[u]+1;
      fa[e[j]]:=u;
      dfs1(e[j]);
      inc(size[u],size[e[j]]);
      if size[e[j]]>size[son[u]] then
        son[u]:=e[j];
      end;
    j:=next[j];
    end;
  end;
procedure dfs2(u:longint);
  var j:longint;
  begin
  v[u]:=true;
  j:=head[u];
  top[son[u]]:=top[u];
  while j<>0 do
    begin
    if not v[e[j]] then
      dfs2(e[j]);
    j:=next[j];
    end;
  end;
procedure dfs3(u:longint);
  var j:longint;
  begin
  v[u]:=true;
  j:=head[u];
  inc(xx);aa[xx]:=u;
  w[u]:=xx;
  if (son[u]<>0)and(not v[son[u]]) then
    dfs3(son[u]);
  while j<>0 do
    begin
    if not v[e[j]] then
      dfs3(e[j]);
    j:=next[j];
    end;
  end;
procedure add(u,v:longint);
  begin
  inc(ee);
  e[ee]:=v;
  next[ee]:=head[u];
  head[u]:=ee;
  end;
procedure build(s,ll,rr:longint);
  begin
  l[s]:=ll;r[s]:=rr;
  if l[s]=r[s] then
    begin
    inc(xx);
    a[s]:=point[aa[xx]];
    b[s]:=a[s];
    end
  else
    begin
    build(s*2,ll,(ll+rr) shr 1);
    build(s*2+1,(ll+rr)shr 1 +1,rr);
    a[s]:=max(a[s*2],a[s*2+1]);
    b[s]:=b[s*2]+b[s*2+1];
    end;
  end;
procedure change(s:longint);
  begin
  if l[s]=r[s] then
    begin
    a[s]:=rr;
    b[s]:=rr;
    end
  else
    begin
    if ll<=r[s*2] then
      change(s*2)
    else change(s*2+1);
    a[s]:=max(a[s*2],a[s*2+1]);
    b[s]:=b[s*2]+b[s*2+1];
    end;
  end;
procedure search(s:longint);
  begin
  if (l[s]>rr)or(r[s]<ll) then exit;
  if (ll<=l[s])and(rr>=r[s]) then
    begin
    ansa:=max(ansa,a[s]);
    ansb:=ansb+b[s];
    end
  else
    begin
    search(s*2);
    search(s*2+1);
    end;
  end;

function getsum(aa,bb:longint):longint;
  var faa,fbb:longint;
  begin
  getsum:=0;
  while aa<>bb do
    begin
    if top[aa]=aa then
      faa:=fa[aa]
    else faa:=top[aa];
    if top[bb]=bb then
      fbb:=fa[bb]
    else fbb:=top[bb];
    if d[faa]>d[fbb] then
      begin
      swap(aa,bb);
      swap(faa,fbb);
      end;
    if TOP[AA]=TOP[BB] then
      begin
      if d[aa]>d[bb] then swap(aa,bb);
      ll:=w[aa];rr:=w[bb];
      if ll>rr then swap(ll,rr);
      ansb:=0;
      search(1);
      inc(getsum,ansb-point[aa]);
      bb:=aa;
      end
    else
      if top[bb]<>fbb then
        begin
        inc(getsum,point[bb]);bb:=fbb;
        end
      else
        begin
        ll:=w[fbb];rr:=w[bb];
        if ll>rr then swap(ll,rr);
        ansb:=0;
        search(1);
        inc(getsum,ansb-point[fbb]);
        bb:=fbb;
        end;
    end;
  inc(getsum,point[aa]);
  end;

function getmax(aa,bb:longint):longint;
  var faa,fbb:longint;
  begin
  getmax:=-maxlongint;
  while aa<>bb do
    begin
    if top[aa]=aa then
      faa:=fa[aa]
    else faa:=top[aa];
    if top[bb]=bb then
      fbb:=fa[bb]
    else fbb:=top[bb];
    if d[faa]>d[fbb] then
      begin
      swap(aa,bb);
      swap(faa,fbb);
      end;
    if top[aa]=top[bb] then
      begin
      if d[aa]>d[bb] then swap(aa,bb);
      ll:=w[aa];rr:=w[bb];
      if ll>rr then swap(ll,rr);
      ansa:=-maxlongint;
      search(1);
      getmax:=max(getmax,ansa);
      bb:=aa;
      end
    else
      if top[bb]<>fbb then
        begin
        getmax:=max(getmax,point[bb]); bb:=fbb;
        end
      else
        begin
        ll:=w[fbb];rr:=w[bb];
        if ll>rr then swap(ll,rr);
        ansa:=-maxlongint;
        search(1);
        getmax:=max(getmax,ansa);
        bb:=fbb;
        end;
    end;
  getmax:=max(getmax,point[aa]);
  end;

begin
  assign(input,'count.in');reset(input);
  assign(output,'count.out');rewrite(output);

  randomize;
  readln(n);
  for i:=1 to n-1 do
    begin
    readln(uu,vv);
    add(uu,vv);
    add(vv,uu);
    end;
  root:=random(n)+1;root:=1;
  d[root]:=1;
  dfs1(root);
  for i:=1 to n do top[i]:=i;
  dfs3(root);
  fillchar(v,sizeof(v),false);
  dfs2(root);
  for i:=1 to n do
    read(point[i]);
  xx:=0;
  build(1,1,n);
  readln(opt);
  for i:=1 to opt do
    begin
    read(ch,ch1);
    if (ch='Q')and(ch1='M') then
      begin
      read(ch,ch,ch);
      readln(pp,qq);
      writeln(getmax(pp,qq));
      end;
    if (ch='Q')and(ch1='S') then
      begin
      read(ch,ch,ch);
      readln(pp,qq);
      writeln(getsum(pp,qq));
      end;
    if (ch='C') then
      begin
      read(ch,ch,ch,ch,ch);
      readln(ll,rr);
      point[ll]:=rr;
      ll:=w[ll];
      change(1);
      end;
    end;
    close(input);
    close(output);
  end.