建出點分樹，每個節點維護其作為點分樹上lca對子樹內點的貢獻，線段樹維護即可，同時另開一個線段樹以減掉父親重復的貢獻。

#include<iostream> 
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
#define ll long long
#define N 100010
char getc(){char c=getchar();while ((c<‘A‘||c>‘Z‘)&&(c<‘a‘||c>‘z‘)&&(c<‘0‘||c>‘9‘)) c=getchar();return c;}
int gcd(int n,int m){return m==0?n:gcd(m,n%m);}
int read()
{
	int x=0,f=1;char c=getchar();
	while (c<‘0‘||c>‘9‘) {if (c==‘-‘) f=-1;c=getchar();}
	while (c>=‘0‘&&c<=‘9‘) x=(x<<1)+(x<<3)+(c^48),c=getchar();
	return x*f;
}
int n,m,p[N],size[N],deep[N],fa[N][19],t;
bool flag[N];
struct data{int to,nxt;
}edge[N<<1];
void addedge(int x,int y){t++;edge[t].to=y,edge[t].nxt=p[x],p[x]=t;}
void dfs(int k)
{
	for (int i=p[k];i;i=edge[i].nxt)
	if (edge[i].to!=fa[k][0])
	{
		fa[edge[i].to][0]=k;
		deep[edge[i].to]=deep[k]+1;
		dfs(edge[i].to);
	}
}
int lca(int x,int y)
{
	if (deep[x]<deep[y]) swap(x,y);
	for (int j=18;~j;j--) if (deep[fa[x][j]]>=deep[y]) x=fa[x][j];
	if (x==y) return x;
	for (int j=18;~j;j--) if (fa[x][j]!=fa[y][j]) x=fa[x][j],y=fa[y][j];
	return fa[x][0];
}
int dis(int x,int y){return deep[x]+deep[y]-(deep[lca(x,y)]<<1);}
namespace newtree
{
	int rt,cnt[2],root[2][N],fa[N];
	struct data{int l,r,x;}tree[2][N<<7];
	void addedge(int x,int y){fa[y]=x;}
	void add(int &k,int l,int r,int p,int x,int op)
	{
		if (!k) k=++cnt[op];
		tree[op][k].x+=x;
		if (l==r) return;
		int mid=l+r>>1;
		if (p<=mid) add(tree[op][k].l,l,mid,p,x,op);
		else add(tree[op][k].r,mid+1,r,p,x,op);
	}
	int sum(int k,int l,int r,int x,int op)
	{
		if (!k) return 0;
		if (l==r) return tree[op][k].x;
		int mid=l+r>>1;
		if (x<=mid) return sum(tree[op][k].l,l,mid,x,op);
		else return tree[op][tree[op][k].l].x+sum(tree[op][k].r,mid+1,r,x,op);
	}
	void modify(int x,int d,int w)
	{
		add(root[0][x],0,n,0,w,0),add(root[0][x],0,n,d+1,-w,0);
		int i=x;
		while (i!=rt)
		{
			int D=dis(x,fa[i]);
			if (D<=d)
				add(root[0][fa[i]],0,n,0,w,0),add(root[0][fa[i]],0,n,d-D+1,-w,0),
				add(root[1][i],0,n,0,-w,1),add(root[1][i],0,n,d-D+1,w,1);
			i=fa[i];
		}
	}
	int query(int x)
	{
		int ans=0,i=x;
		while (i) ans+=sum(root[0][i],0,n,dis(x,i),0),ans+=sum(root[1][i],0,n,dis(x,fa[i]),1),i=fa[i];
		return ans;
	}
}
void make(int k,int from)
{
	size[k]=1;
	for (int i=p[k];i;i=edge[i].nxt)
	if (!flag[edge[i].to]&&edge[i].to!=from)
	{
		make(edge[i].to,k);
		size[k]+=size[edge[i].to];
	}
}
int findroot(int k,int from,int s)
{
	int mx=0;
	for (int i=p[k];i;i=edge[i].nxt)
	if (!flag[edge[i].to]&&edge[i].to!=from&&size[edge[i].to]>size[mx]) mx=edge[i].to;
	if ((size[mx]<<1)>s) return findroot(mx,k,s);
	else return k;
}
int build(int k)
{
	make(k,k);
	flag[k=findroot(k,k,size[k])]=1;
	for (int i=p[k];i;i=edge[i].nxt)
	if (!flag[edge[i].to]) newtree::addedge(k,build(edge[i].to));
	return k;
}
int main()
{
#ifndef ONLINE_JUDGE
	freopen("bzoj4372.in","r",stdin);
	freopen("bzoj4372.out","w",stdout);
	const char LL[]="%I64d\n";
#else
	const char LL[]="%lld\n";
#endif
	n=read(),m=read();
	for (int i=1;i<n;i++)
	{
		int x=read(),y=read();
		addedge(x,y),addedge(y,x);
	}
	fa[1][0]=1;dfs(1);
	for (int j=1;j<19;j++)
		for (int i=1;i<=n;i++)
		fa[i][j]=fa[fa[i][j-1]][j-1];
	newtree::rt=build(1);
	while (m--)
	{
		char c=getc();
		if (c==‘M‘)
		{
			int x=read(),d=read(),w=read();
			newtree::modify(x,d,w);
		}
		else printf("%d\n",newtree::query(read()));
	}
	return 0;
}

BZOJ4372 爍爍的遊戲（動態點分治+線段樹）