题目不难，模拟即可。

文件操作请自行删除。

#include <bits/stdc++.h>
using namespace std;
vector<pair<int, int> > gv[100001];
int sm[100001];
// Add an edge of length n between u and v.
void add_edge(int u, int v, int n){
    gv[u].push_back(make_pair(v, n));
    gv[v].push_back(make_pair(u, n));
}
// Calculates The smallest length of the path from i to the root.
void dfs(int n, int fa){
    for(int i = 0;i < gv[n].size();i++){
        if(gv[n][i].first == fa){
            continue;
        }
        sm[gv[n][i].first] = min(sm[n], gv[n][i].second);
        dfs(gv[n][i].first, n);
    }
}
int main(){
    freopen("mootube.in", "r", stdin);
    freopen("mootube.out", "w", stdout);
    int n, q;
    cin >> n >> q;
    for(int i = 0;i < n - 1;i++){
        int u, v, x;
        cin >> u >> v >> x;
        add_edge(u, v, x);
    }
    for(int i = 0;i < q;i++){
        int k, v;
        cin >> k >> v;
        memset(sm, 0x3f3f3f3f, sizeof(sm));
        dfs(v, -1);
        sm[v] = 0;
        int ans = 0;
        for(int j = 1;j <= n;j++){
            if(sm[j] >= k){
                ans++;
            }
        }
        cout << ans << endl;
    }
    fclose(stdin), fclose(stdout);
    return 0;
}