#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;
int n, m;
vector<vector<int>> v;
vector<int> s, t;
vector<vector<int>> sth;
vector<vector<int>> sth2;
vector<int> state;
vector<int> p;
vector<int> d;
bool cycle;
void dfs1(int nd, int ss, int dis){
for(int x: v[nd]) if(x != ss) dfs1(x, nd, dis+1);
p[nd] = ss;
d[nd] = dis;
}
void dfs2(int nd){
if(state[nd] == 1){
cycle = 1;
return;
}
if(state[nd] == 2) return;
state[nd] = 1;
for(int x: sth[nd]) dfs2(x);
state[nd] = 2;
}
void solve(){
cin >> n;
v.assign(n, {});
p.assign(n, 0);
d.assign(n, 0);
sth.assign(n, {});
sth2.assign(n, {});
state.assign(n, 0);
for(int i = 0; i < n-1; i++){
int a, b; cin >> a >> b; a--, b--;
v[a].pb(b);
v[b].pb(a);
}
dfs1(0, -1, 0);
cin >> m;
s.assign(m, 0);
t.assign(m, 0);
for(int i = 0; i < m; i++) cin >> s[i] >> t[i], s[i]--, t[i]--;
vector<int> ss(n, -1), tt(n, -1);
for(int i = 0; i < m; i++) ss[s[i]] = i, tt[t[i]] = i;
auto get_path = [&](int a, int b){
vector<int> rt;
if(d[a] > d[b]) swap(a, b);
while(d[a] != d[b]) rt.pb(b), b = p[b];
while(a != b) rt.pb(a), rt.pb(b), a = p[a], b = p[b];
rt.pb(a);
return rt;
};
for(int i = 0; i < m; i++){
unordered_map<int, int> cnt;
for(int x: get_path(s[i], t[i])){
if(ss[x] != -1 && ss[x] != i) cnt[ss[x]]++, sth[i].pb(ss[x]);
//if(tt[x] != -1 && tt[x] != i) cnt[tt[x]]++, sth[tt[x]].pb(i);
}
for(auto [ig, x]: cnt) if(x > 1){
cout << "No\n";
return;
}
}
cycle = 0;
for(int i = 0; i < n; i++) if(state[i] == 0) dfs2(i);
for(int i = 0; i < m; i++){
unordered_map<int, int> cnt;
for(int x: get_path(s[i], t[i])){
if(ss[x] != -1 && ss[x] != i) cnt[ss[x]]++, sth[i].pb(ss[x]);
//if(tt[x] != -1 && tt[x] != i) cnt[tt[x]]++, sth[tt[x]].pb(i);
}
for(auto [ig, x]: cnt) if(x > 1){
cout << "No\n";
return;
}
}
for(int i = 0; i < n; i++) if(state[i] == 0) dfs2(i);
cout << (cycle?"No\n":"Yes\n");
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int T; cin >> T; while(T--) solve();
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Incorrect |
10 ms |
340 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
232 KB |
Output is correct |
5 |
Incorrect |
14 ms |
212 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Incorrect |
10 ms |
340 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |