이 제출은 이전 버전의 oj.uz에서 채점하였습니다. 현재는 제출 당시와는 다른 서버에서 채점을 하기 때문에, 다시 제출하면 결과가 달라질 수도 있습니다.
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int q; cin>>q;
while (q--){
int n; cin>>n;
vector<int> g[n + 1];
for (int i = 1; i < n; i++){
int a, b; cin>>a>>b;
g[a].push_back(b);
g[b].push_back(a);
}
int m; cin>>m;
vector<int> s(m + 1), t(m + 1), used(n + 1);
for (int i = 1; i <= m; i++){
cin>>s[i]>>t[i];
used[s[i]] = i;
}
vector<int> tin(n + 1), tout(n + 1), p(n + 1), pp(n + 1);
int lg = ceil(log2(n)) + 1;
vector<int> pw[n + 1];
for (int i = 1; i <= n; i++){
p[i] = i;
pw[i].resize(lg);
}
int timer = 0;
function<void(int, int)> fill = [&](int v, int pr){
tin[v] = ++timer;
pw[v][0] = pp[v] = pr;
for (int i = 1; i < lg; i++){
pw[v][i] = pw[pw[v][i - 1]][i - 1];
}
for (int i: g[v]){
if (i == pr) continue;
fill(i, v);
}
tout[v] = timer;
};
fill(1, 1);
pp[1] = 0;
auto check = [&](int x, int y){
return (tin[x] <= tin[y] && tout[x] >= tout[y]);
};
auto lca = [&](int x, int y){
if (check(x, y)) return x;
if (check(y, x)) return y;
for (int i = lg - 1; i >= 0; i--){
if (!check(pw[x][i], y)){
x = pw[x][i];
}
}
return pw[x][0];
};
vector<int> l(m + 1);
for (int i = 1; i <= m; i++){
l[i] = lca(s[i], t[i]);
}
function<int(int)> get = [&](int v){
if (!v || used[v]) return v;
if (p[v] == v){
p[v] = pp[v];
}
return p[v] = get(p[v]);
};
vector<int> order;
vector<bool> vis(n + 1);
bool out = true;
function<void(int)> dfs = [&](int v){
if (vis[v]){
out = false;
return;
}
vis[v] = true;
if (!used[s[v]]) return;
used[s[v]] = 0;
int x;
while (check(l[v], x = get(s[v]))){
dfs(used[x]);
}
while (check(l[v], x = get(t[v]))){
dfs(used[x]);
}
used[t[v]] = v;
order.push_back(v);
};
vector<bool> k(n + 1);
for (int i = 1; i <= m; i++){
k[s[i]] = true;
}
for (int i = 1; i <= m; i++){
dfs(i);
}
cout<<((out == true) ? "Yes" : "No")<<"\n";
}
}
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