#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
const int N_MAX = 1.2e5 + 11;
const int LG_N = 20;
vector<int> G[N_MAX], H[N_MAX];
vector<pair<int, int>> Q;
int anc[LG_N][N_MAX], p[N_MAX], d[N_MAX];
int owner[N_MAX];
bool vis[N_MAX];
bool in_stack[N_MAX];
int n, q;
void clear(){
for(int i = 0; i <= n; i++) G[i].clear();
for(int i = 0; i <= n; i++) H[i].clear();
fill(owner, owner + n + 1, 0);
fill(vis, vis + n + 1, 0);
fill(in_stack, in_stack + n + 1, 0);
Q.clear();
}
void dfs(int v, int pa = -1){
for(auto i : G[v]){
if(i != pa){
p[i] = anc[0][i] = v; d[i] = d[v] + 1;
for(int j = 1; j < LG_N; j++){
anc[j][i] = anc[j - 1][anc[j - 1][i]];
}
dfs(i, v);
}
}
}
bool dfs2(int v){
vis[v] = in_stack[v] = true;
for(auto i : H[v]){
if(in_stack[i]) return true;
if(vis[i]) continue;
bool fail = dfs2(i);
if(fail) return true;
}
in_stack[v] = false;
return false;
}
int kth_anc(int u, int k){
for(int j = LG_N - 1; j >= 0; j--){
if(k & (1 << j)) u = anc[j][u];
}
return u;
}
int lca(int u, int v){
if(d[u] < d[v]) swap(u, v);
u = kth_anc(u, d[u] - d[v]);
for(int j = LG_N - 1; j >= 0; j--){
if(anc[j][u] != anc[j][v]){
u = anc[j][u], v = anc[j][v];
}
}
return u == v ? u : p[u];
}
void solve(){
cin >> n;
for(int i = 0; i < n - 1; i++){
int u, v; cin >> u >> v;
G[u].push_back(v);
G[v].push_back(u);
}
dfs(1);
cin >> q;
Q.push_back({-1, -1});
for(int i = 1; i <= q; i++){
int x, y; cin >> x >> y;
Q.push_back({x, y});
owner[x] = i;
}
for(int i = 1; i <= q; i++){
auto [x, y] = Q[i]; int l = lca(x, y);
vector<int> P, p1, p2;
while(x != l){
p1.push_back(x); x = p[x];
}
while(y != l){
p2.push_back(y); y = p[y];
}
for(auto i : p1) P.push_back(i);
P.push_back(l);
reverse(p2.begin(), p2.end());
for(auto i : p2) P.push_back(i);
for(auto p : P) {
if(owner[p] && owner[p] != i){
H[i].push_back(owner[p]);
}
}
}
bool fail = false;
for(int i = 1; i <= q; i++){
if(!vis[i]) fail |= dfs2(i);
if(fail) break;
}
cout << (!fail ? "Yes" : "No") << endl;
}
int32_t main(){
int q; cin >> q;
while(q--){
solve();
clear();
}
}
Compilation message
jail.cpp: In function 'void solve()':
jail.cpp:83:8: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
83 | auto [x, y] = Q[i]; int l = lca(x, y);
| ^
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
5972 KB |
Output is correct |
2 |
Correct |
4 ms |
5948 KB |
Output is correct |
3 |
Correct |
3 ms |
5972 KB |
Output is correct |
4 |
Incorrect |
26 ms |
6396 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
5972 KB |
Output is correct |
2 |
Correct |
4 ms |
5948 KB |
Output is correct |
3 |
Incorrect |
5 ms |
6084 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
5972 KB |
Output is correct |
2 |
Correct |
4 ms |
5948 KB |
Output is correct |
3 |
Incorrect |
5 ms |
6084 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
5972 KB |
Output is correct |
2 |
Correct |
4 ms |
5948 KB |
Output is correct |
3 |
Incorrect |
5 ms |
6084 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
5972 KB |
Output is correct |
2 |
Correct |
4 ms |
5948 KB |
Output is correct |
3 |
Incorrect |
5 ms |
6084 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
5972 KB |
Output is correct |
2 |
Correct |
4 ms |
5944 KB |
Output is correct |
3 |
Correct |
4 ms |
5948 KB |
Output is correct |
4 |
Correct |
4 ms |
5972 KB |
Output is correct |
5 |
Incorrect |
19 ms |
6224 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
5972 KB |
Output is correct |
2 |
Correct |
4 ms |
5948 KB |
Output is correct |
3 |
Correct |
3 ms |
5972 KB |
Output is correct |
4 |
Incorrect |
26 ms |
6396 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |