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mootube.cpp
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mootube.cpp
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#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
template <typename T1, typename T2>
ostream &operator <<(ostream &os, pair<T1, T2> p){os << p.first << " " << p.second; return os;}
template <typename T>
ostream &operator <<(ostream &os, vector<T> &v){for(T i : v)os << i << ", "; return os;}
template <typename T>
ostream &operator <<(ostream &os, set<T> s){for(T i : s) os << i << ", "; return os;}
template <typename T1, typename T2>
ostream &operator <<(ostream &os, map<T1, T2> m){for(pair<T1, T2> i : m) os << i << endl; return os;}
int find(int u, int (&par)[100000]){
if(par[u] == u){
return u;
}
par[u] = find(par[u], par);
return par[u];
}
void un(int u, int v, int (&par)[100000], int (&sz)[100000]){
u = find(u, par);
v = find(v, par);
if(u == v){
return;
}
if(sz[u] < sz[v]){
par[u] = v;
sz[v] += sz[u];
}else{
par[v] = u;
sz[u] += sz[v];
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
freopen("mootube.in", "r", stdin);
freopen("mootube.out", "w", stdout);
int N, Q; cin >> N >> Q;
vector<pair<int, pii>> edges;
for(int i = 0; i < N-1; i++){
int u, v, r; cin >> u >> v >> r;
edges.push_back(make_pair(r, pii(u-1, v-1)));
}
sort(edges.begin(), edges.end(), greater<pair<int, pii>>());
pair<pii, int> query[Q];
for(int i = 0; i < Q; i++){
cin >> query[i].first.first >> query[i].first.second;
query[i].first.second--;
query[i].second = i;
}
sort(query, query+Q, greater<pair<pii, int>>());
int par[100000], sz[100000];
for(int i = 0; i < N; i++){
par[i] = i;
sz[i] = 1;
}
int edgePtr = 0;
int ans[Q];
for(int i = 0; i < Q; i++){
int ki = query[i].first.first, vi = query[i].first.second, idx = query[i].second;
while(edgePtr < N && edges[edgePtr].first >= ki){
un(edges[edgePtr].second.first, edges[edgePtr].second.second, par, sz);
edgePtr++;
}
ans[idx] = sz[find(vi, par)]-1;
}
for(int i = 0; i < Q; i++){
cout << ans[i] << endl;
}
return 0;
}