[BZOJ3531] [SDOI2014] 旅行

传送门

http://www.lydsy.com/JudgeOnline/problem.php?id=3531

题目大意

给定一棵树，每个点有一个权值和一个颜色，多次改变一些点的权值和颜色，多次求一条路径上与起点和终点颜色相同的点的权值和以及权值最大值

题解

按照颜色建颜色种类棵线段树，当然明显内存承受不了，所以我们动态开点，不明白的看代码

const
maxn=100050;
var
w:array[0..3*maxn,1..2]of longint;
ls,rs,summ,maxx:array[0..20*maxn]of longint;
x,y,size,fa,dep,son,top,pos,root:array[0..maxn]of longint;
i,j,k:longint;
n,m,len,tot,a,b:longint;
c1,c2:char; st:string;
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 init(a,b:longint);
begin
w[len,1]:=b;
if w[a,2]=0 then w[a,2]:=len else w[w[a,1],2]:=len;
w[a,1]:=len; inc(len);
end;

procedure dfs1(a:longint); {fa,size,son,dep}
var tt,v:longint;
begin
tt:=w[a,2]; v:=0; size[a]:=1;
while tt<>0 do
begin
if w[tt,1]<>fa[a]
then
begin
fa[w[tt,1]]:=a; dep[w[tt,1]]:=dep[a]+1;
dfs1(w[tt,1]);
inc(size[a],size[w[tt,1]]); if size[w[tt,1]]>size[v] then v:=w[tt,1];
end;
tt:=w[tt,2];
end;
son[a]:=v;
end;

procedure dfs2(a,pre:longint); {top,pos}
var tt:longint;
begin
tt:=w[a,2]; inc(len); pos[a]:=len; top[a]:=pre;
if son[a]<>0 then dfs2(son[a],pre);
while tt<>0 do
begin
if (w[tt,1]<>fa[a])and(w[tt,1]<>son[a]) then dfs2(w[tt,1],w[tt,1]);
tt:=w[tt,2];
end;
end;

procedure insert(var a:longint; l,r,b,val:longint);
var mid:longint;
begin
if a=0 then begin inc(tot); a:=tot; end;
inc(summ[a],val); maxx[a]:=max(maxx[a],val);
if l=r then exit;
mid:=(l+r)>>1;
if b<=mid
then insert(ls[a],l,mid,b,val)
else insert(rs[a],mid+1,r,b,val);
end;

procedure update(var a:longint; l,r,b,val:longint);
var mid:longint;
begin
if a=0 then begin inc(tot); a:=tot; end;
inc(summ[a],val);
if l=r then begin inc(maxx[a],val); exit; end;
mid:=(l+r)>>1;
if b<=mid
then update(ls[a],l,mid,b,val)
else update(rs[a],mid+1,r,b,val);
maxx[a]:=max(maxx[ls[a]],maxx[rs[a]]);
end;

function querysum(a,l,r,b,c:longint):longint;
var mid:longint;
begin
if (l=b)and(r=c) then exit(summ[a]);
mid:=(b+c)>>1;
if r<=mid then exit(querysum(ls[a],l,r,b,mid)) else
if l>mid then exit(querysum(rs[a],l,r,mid+1,c))
else exit(querysum(ls[a],l,mid,b,mid)+querysum(rs[a],mid+1,r,mid+1,c));
end;

function querymax(a,l,r,b,c:longint):longint;
var mid:longint;
begin
if (l=b)and(r=c) then exit(maxx[a]);
mid:=(b+c)>>1;
if r<=mid then exit(querymax(ls[a],l,r,b,mid)) else
if l>mid then exit(querymax(rs[a],l,r,mid+1,c))
else exit(max(querymax(ls[a],l,mid,b,mid),querymax(rs[a],mid+1,r,mid+1,c)));
end;

procedure cc;
begin
readln(a,b);
update(root[y[a]],1,n,pos[a],-x[a]);
y[a]:=b;
insert(root[y[a]],1,n,pos[a],x[a]);
end;

procedure cw;
begin
readln(a,b);
update(root[y[a]],1,n,pos[a],b-x[a]);
x[a]:=b;
end;

procedure qs;
var kind,ans:longint;
begin
readln(a,b); kind:=y[a]; ans:=0;
while top[a]<>top[b] do
begin
if dep[top[a]]<dep[top[b]] then swap(a,b);
inc(ans,querysum(root[kind],pos[top[a]],pos[a],1,n));
a:=fa[top[a]];
end;
if dep[a]>dep[b] then swap(a,b);
inc(ans,querysum(root[kind],pos[a],pos[b],1,n));
writeln(ans);
end;

procedure qm;
var kind,ans:longint;
begin
readln(a,b); kind:=y[a]; ans:=-maxlongint;
while top[a]<>top[b] do
begin
if dep[top[a]]<dep[top[b]] then swap(a,b);
ans:=max(ans,querymax(root[kind],pos[top[a]],pos[a],1,n));
a:=fa[top[a]];
end;
if dep[a]>dep[b] then swap(a,b);
ans:=max(ans,querymax(root[kind],pos[a],pos[b],1,n));
writeln(ans);
end;

begin
readln(n,m); len:=n+1;
for i:=1 to n do
readln(x[i],y[i]);
for i:=1 to n-1 do
begin readln(a,b); init(a,b); init(b,a); end;
dep[1]:=1; size[0]:=0;
dfs1(1);
len:=0;
dfs2(1,1);
tot:=0; summ[0]:=0; maxx[0]:=0;
for i:=1 to n do
insert(root[y[i]],1,n,pos[i],x[i]);
for i:=1 to m do
begin
read(c1,c2);
case c2 of
'C':cc;
'W':cw;
'S':qs;
'M':qm;
end;
end;
end.