bzoj3531

不难想到树链剖分
这题的难点是记录的是路径上宗教相同的点
裸的想法是对每一种宗教都开一棵线段树，记录每个点的评级
但显然这样会爆空间，仔细分析一下，这些线段树内很多点压根就没用到
因此我们考虑对线段树动态开点，不难发现每次修改最多要开线段树上O(2*logn)个点，是可以接受的
然后就是打码的问题了

 type node=record
        po,next:longint;
      end;
      link=record
        l,r,s,m:longint;
      end;

 var tree:array[..*] of link;
     fa,size,d,top,p,c,h,b,w:array[..] of longint;
     e:array[..] of node;
     len,t,i,n,q,x,y:longint;
     ch:char;

 function max(a,b:longint):longint;
   begin
     if a>b then exit(a) else exit(b);
   end;

 procedure swap(var a,b:longint);
   var c:longint;
   begin
     c:=a;
     a:=b;
     b:=c;
   end;

 procedure add(x,y:longint);
   begin
     inc(len);
     e[len].po:=y;
     e[len].next:=p[x];
     p[x]:=len;
   end;

 procedure update(x:longint);
   begin
     tree[x].s:=tree[tree[x].l].s+tree[tree[x].r].s;
     tree[x].m:=max(tree[tree[x].l].m,tree[tree[x].r].m);
   end;

 procedure dfs1(x:longint);
   var i,y:longint;
   begin
     size[x]:=;
     i:=p[x];
     while i<> do
     begin
       y:=e[i].po;
       if fa[x]<>y then
       begin
         d[y]:=d[x]+;
         fa[y]:=x;
         dfs1(y);
         size[x]:=size[x]+size[y];
       end;
       i:=e[i].next;
     end;
   end;

 procedure dfs2(x:longint);
   var i,y,q:longint;
   begin
     q:=;
     inc(t);
     c[x]:=t;
     i:=p[x];
     while i<> do
     begin
       y:=e[i].po;
       if (c[y]=) and (size[y]>size[q]) then q:=y;
       i:=e[i].next;
     end;
     if q<> then
     begin
       top[q]:=top[x];
       dfs2(q);
     end;
     i:=p[x];
     while i<> do
     begin
       y:=e[i].po;
       if c[y]= then
       begin
         top[y]:=y;
         dfs2(y);
       end;
       i:=e[i].next;
     end;
   end;

 function change(last,l,r,x,y:longint):longint;
   var m,q:longint;
   begin
     inc(t);
     if l=r then
     begin
       tree[t].m:=y;
       tree[t].s:=y;
       exit(t);
     end
     else begin
       m:=(l+r) shr ;
       q:=t;
       if x<=m then
       begin
         tree[q].r:=tree[last].r;
         last:=tree[last].l;
         tree[q].l:=change(last,l,m,x,y);
       end
       else begin
         tree[q].l:=tree[last].l;
         last:=tree[last].r;
         tree[q].r:=change(last,m+,r,x,y);
       end;
       update(q);
       exit(q);
     end;
   end;

 function getmax(now,l,r,x,y:longint):longint;
   var m,q:longint;
   begin
     if (x<=l) and (y>=r) then exit(tree[now].m)
     else begin
       m:=(l+r) shr ;
       q:=;
       if (x<=m) and (tree[now].l<>) then q:=getmax(tree[now].l,l,m,x,y);
       if (y>m) and (tree[now].r<>) then q:=max(q,getmax(tree[now].r,m+,r,x,y));
       exit(q);
     end;
   end;

 function getsum(now,l,r,x,y:longint):longint;
   var m,q:longint;
   begin
     if (x<=l) and (y>=r) then exit(tree[now].s)
     else begin
       m:=(l+r) shr ;
       q:=;
       if (x<=m) and (tree[now].l<>) then q:=q+getsum(tree[now].l,l,m,x,y);
       if (y>m) and (tree[now].r<>) then q:=q+getsum(tree[now].r,m+,r,x,y);
       exit(q);
     end;
   end;

 function maxx(x,y:longint):longint;
   var f1,f2,re:longint;
   begin
     maxx:=;
     re:=b[x];
     f1:=top[x];
     f2:=top[y];
     while f1<>f2 do
     begin
       if d[f1]>=d[f2] then
       begin
         maxx:=max(maxx,getmax(h[re],,n,c[f1],c[x]));
         x:=fa[f1];
       end
       else begin
         maxx:=max(maxx,getmax(h[re],,n,c[f2],c[y]));
         y:=fa[f2];
       end;
       f1:=top[x];
       f2:=top[y];
     end;
     if c[x]>c[y] then swap(x,y);
     maxx:=max(maxx,getmax(h[re],,n,c[x],c[y]));
   end;

 function ask(x,y:longint):longint;
   var f1,f2,re:longint;
   begin
     ask:=;
     re:=b[x];
     f1:=top[x];
     f2:=top[y];
     while f1<>f2 do
     begin
       if d[f1]>=d[f2] then
       begin
         ask:=ask+getsum(h[re],,n,c[f1],c[x]);
         x:=fa[f1];
       end
       else begin
         ask:=ask+getsum(h[re],,n,c[f2],c[y]);
         y:=fa[f2];
       end;
       f1:=top[x];
       f2:=top[y];
     end;
     if c[x]>c[y] then swap(x,y);
     ask:=ask+getsum(h[re],,n,c[x],c[y]);
   end;

 begin
   readln(n,q);
   for i:= to n do
     readln(w[i],b[i]);
   for i:= to n- do
   begin
     readln(x,y);
     add(x,y);
     add(y,x);
   end;
   d[]:=;
   dfs1();
   top[]:=;
   dfs2();
   t:=;
   for i:= to n do
     h[b[i]]:=change(h[b[i]],,n,c[i],w[i]);
   for i:= to q do
   begin
     read(ch);
     if ch='C' then
     begin
       readln(ch,x,y);
       if ch='C' then
       begin
         h[b[x]]:=change(h[b[x]],,n,c[x],);
         b[x]:=y;
         h[y]:=change(h[y],,n,c[x],w[x]);
       end
       else begin
         w[x]:=y;
         h[b[x]]:=change(h[b[x]],,n,c[x],y);
       end;
     end
     else begin
       readln(ch,x,y);
       if ch='M' then
         writeln(maxx(x,y))
       else writeln(ask(x,y));
     end;
   end;
 end.