#include<bits/stdc++.h>
using namespace std;
const int nax = 120001;
const int lg = 17;
vector<int>g[nax], t[nax];
int n, m;
int bed[nax], work[nax];
int sp[nax][lg];
int tt = 0, st[nax], en[nax];
int vis[nax], dep[nax];
void dfs(int v, int p = 1, int d = 0) {
dep[v] = d;
sp[v][0] = p;
st[v] = tt++;
for(int j=1; j<lg; ++j) {
sp[v][j] = sp[sp[v][j-1]][j-1];
}
for(int u : g[v]) if(u!=p) {
dfs(u, v, d+1);
}
en[v] = tt-1;
}
bool anc(int u, int v) {
return st[u] <= st[v] && en[u] >= en[v];
}
int LIFT(int u, int v) {
for(int j=lg-1; j>=0; --j) if(!anc(sp[u][j], v)) {
u = sp[u][j];
}
if(!anc(u, v)) u = sp[u][0];
return u;
}
bool lies(int u, int v, int lca, int x) {
if(anc(lca, x)) {
return anc(x, u) || anc(x, v);
}
return false;
}
int bond(int i, int j) {
int lca1 = LIFT(bed[i], work[i]);
int lca2 = LIFT(bed[j], work[j]);
int len1 = dep[bed[i]] + dep[work[i]] - 2 * dep[lca1];
int len2 = dep[bed[j]] + dep[work[j]] - 2 * dep[lca2];
if(len1 < len2) {
swap(i, j);
swap(len1, len2);
swap(lca1, lca2);
}
bool f = lies(bed[i], work[i], lca1, bed[j]);
bool ff = lies(bed[i], work[i], lca1, work[j]);
if(f && ff) return 1;
if(f) t[j].push_back(i);
if(ff) t[i].push_back(j);
return 0;
}
int go(int v) {
vis[v] = 1;
for(int u : t[v]) {
if(!vis[u]) {
if(go(u)) return 1;
} else {
if(vis[u]==1) return 1;
}
}
vis[v] = 2;
return 0;
}
void PlayGround() {
cin>>n;
for(int i=1; i<=n; ++i) {
g[i].clear(), t[i].clear(), tt = vis[i] = 0;
}
for(int i=0; i<n-1; ++i) {
int u, v;
cin>>u>>v;
g[u].push_back(v);
g[v].push_back(u);
}
cin>>m;
for(int i=1; i<=m; ++i) {
cin>>bed[i]>>work[i];
}
dfs(1);
for(int i=1; i<=m; ++i) {
for(int j=i+1; j<=m; ++j) {
if(bond(i, j)) {
cout<<"No\n";
return;
}
}
}
for(int i=1; i<=m; ++i) if(!vis[i]) {
if(go(i)) {
cout<<"No\n";
return;
}
}
cout<<"Yes\n";
// cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int tc;
cin>>tc;
while(tc--) {
PlayGround();
}
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
5972 KB |
Output is correct |
2 |
Correct |
4 ms |
5972 KB |
Output is correct |
3 |
Correct |
3 ms |
5972 KB |
Output is correct |
4 |
Incorrect |
17 ms |
6364 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
5960 KB |
Output is correct |
2 |
Correct |
3 ms |
5972 KB |
Output is correct |
3 |
Incorrect |
4 ms |
6072 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
5960 KB |
Output is correct |
2 |
Correct |
3 ms |
5972 KB |
Output is correct |
3 |
Incorrect |
4 ms |
6072 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
5960 KB |
Output is correct |
2 |
Correct |
3 ms |
5972 KB |
Output is correct |
3 |
Incorrect |
4 ms |
6072 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
5960 KB |
Output is correct |
2 |
Correct |
3 ms |
5972 KB |
Output is correct |
3 |
Incorrect |
4 ms |
6072 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
4 ms |
5972 KB |
Output is correct |
2 |
Correct |
3 ms |
5972 KB |
Output is correct |
3 |
Correct |
3 ms |
5972 KB |
Output is correct |
4 |
Correct |
3 ms |
5972 KB |
Output is correct |
5 |
Incorrect |
13 ms |
6100 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
5972 KB |
Output is correct |
2 |
Correct |
4 ms |
5972 KB |
Output is correct |
3 |
Correct |
3 ms |
5972 KB |
Output is correct |
4 |
Incorrect |
17 ms |
6364 KB |
Output isn't correct |
5 |
Halted |
0 ms |
0 KB |
- |