好题，发现没有强制在线，可以离线操作

排序之后带集合点数的并查集就好了

#include<bits/stdc++.h>
using namespace std;
const int N = 1e5+10;
int n,m;
int p[N],sz[N];

int find(int x){
	if(x!=p[x])p[x] = find(p[x]);
	return p[x];
}
struct Node{
	int k,v,id;
	bool operator<(const Node&W)const{
		return k>W.k;
	}
}query[N];
struct Edge{
	int p,q,r;
	bool operator<(const Edge&Ws)const{
		return r>Ws.r;
	}
}edge[N];
vector<int>ans(100020,0);
int main()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)p[i] = i,sz[i] = 1;
	for(int i=1;i<=n-1;i++){
		int p,q,r;cin>>p>>q>>r;
		edge[i] = {p,q,r};
	}
	
	for(int i=1;i<=m;i++){
		int k,v;cin>>k>>v;
		query[i] = {k,v,i};
	}
	
	sort(edge+1,edge+1+n-1);
	sort(query+1,query+1+m);
	for(int i=1,j=0;i<=m;i++){
		int ks = query[i].k;
		while(j+1<=n&&edge[j+1].r>=ks){
			++j;
			int a = find(edge[j].p),b = find(edge[j].q);
			if(a!=b){
				sz[b]+=sz[a];
				p[a] = b;
			}
		}
		
		ans[query[i].id] = sz[find(query[i].v)]-1;
		
	}
	
	for(int i=1;i<=m;i++)cout<<ans[i]<<"\n";
}