#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
int n, q, kor=0, brl=0, ans=0, par[300005];
vector<int> gr[300005];
bool used[300005];
int lst[300005], gol[300005];
void dfs(int v)
{
gol[v]=1;
used[v]=1;
int brs=gr[v].size();
if(brs==1) {brl++; lst[v]=1;}
for(int i=0; i<brs; i++)
{
int nv=gr[v][i];
if(used[nv]) continue;
par[nv]=v;
dfs(nv);
lst[v]+=lst[nv];
gol[v]+=gol[nv];
}
if(v!=kor && !(lst[v]&1)) ans++;
}
int nvt[300005];
int brchains=1, tv=0;
int chain[300005][2];
int to_chain[300005];
int red[300005], pos[300005];
int stojnost[300005];
void create_hld(int v)
{
tv++;
red[tv]=v;
pos[v]=tv;
to_chain[v]=brchains;
int brs=gr[v].size();
if(!brs) return;
create_hld(gr[v][0]);
for(int i=1; i<brs; i++)
{
chain[brchains][1]=tv;
chain[brchains+1][0]=tv+1;
brchains++;
create_hld(gr[v][i]);
}
}
bool promlst[300005];
bool osob[300005];
int otg[300005];
int pref[300005];
int prom[300005], brprom=0;
int smqna[300005];
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>n>>q;
for(int i=0; i<n-1; i++)
{
int a, b;
cin>>a>>b;
gr[a].push_back(b);
gr[b].push_back(a);
}
for(int i=1; i<=n; i++) if(gr[i].size()>1 && !kor) kor=i;
dfs(kor);
for(int i=1; i<=n; i++)
{
int brs=gr[i].size();
if(i==kor) brs++;
for(int j=0; j<brs-1; j++)
{
int nv=gr[i][j];
if(par[i]==nv) swap(gr[i][j], gr[i][brs-1]);
else if(gol[nv]>gol[gr[i][0]]) swap(gr[i][j], gr[i][0]);
}
gr[i].resize(brs-1);
}
/**
for(int i=1; i<=n; i++)
{
cout<<"Vryh "<<i<<": {";
for(int j=0; j<gr[i].size(); j++) cout<<gr[i][j]<<" ";
cout<<"}\n";
}*/
chain[1][0]=1;
create_hld(kor);
chain[brchains][1]=n;
/**
for(int i=1; i<=n; i++) cout<<red[i]<<" ";
cout<<endl<<brchains<<endl;
for(int i=1; i<=brchains; i++) cout<<chain[i][0]<<" "<<chain[i][1]<<endl;
for(int i=1; i<=n; i++) cout<<pos[i]<<" ";
cout<<endl;
for(int i=1; i<=n; i++) cout<<to_chain[i]<<" ";
cout<<endl;*/
for(int i=1; i<=n; i++)
{
if(i!=kor && !(lst[i]&1)) {otg[pos[i]]=1;}
}
for(int i=1; i<=n; i++) pref[i]=otg[i]+pref[i-1];
for(int i=0; i<q; i++)
{
int d, brl=lst[kor], otgov=0;
brprom=0;
cin>>d;
brl+=d;
for(int i=0; i<d; i++)
{
cin>>nvt[i];
if(nvt[i]==kor) continue;
if(!promlst[nvt[i]] && !gr[nvt[i]].size())
{
brl--;
promlst[nvt[i]]=1;
osob[i]=1;
continue;
}
int tekchain=to_chain[nvt[i]], tpos=pos[nvt[i]], tv=nvt[i];
while(tekchain!=1)
{
int lpos=chain[tekchain][0];
/// cout<<lpos<<" "<<tpos<<endl;
prom[brprom]=lpos;
smqna[lpos]^=1;
brprom++;
prom[brprom]=tpos+1;
smqna[tpos+1]^=1;
brprom++;
tv=par[red[lpos]];
tpos=pos[tv];
tekchain=to_chain[tv];
}
if(tpos>1)
{
prom[brprom]=2;
smqna[2]^=1;
brprom++;
prom[brprom]=tpos+1;
smqna[tpos+1]^=1;
brprom++;
}
}
sort(prom, prom+brprom);
int lpos=1, tsm=0;
for(int i=0; i<brprom; i++)
{
int npos=prom[i];
if(!smqna[prom[i]]) continue;
smqna[prom[i]]=0;
if(!tsm) otgov+=pref[npos-1]-pref[lpos-1];
else otgov+=(npos-lpos)-(pref[npos-1]-pref[lpos-1]);
tsm^=1;
lpos=npos;
}
///cout<<brprom<<" "<<tsm<<" "<<pref[n]<<endl;
if(lpos<=n && !tsm) otgov+=pref[n]-pref[lpos-1];
else if(lpos<=n) otgov+=(n-lpos+1)-(pref[n]-pref[lpos-1]);
if(brl&1) cout<<-1<<endl;
else cout<<n-1+d+otgov<<endl;
brprom=0;
}
return 0;
}
/*
12 3
1 3
4 1
9 1
8 3
3 7
10 2
11 2
2 6
4 5
4 6
9 12
3 1 4 7
2 5 8
1 12
7 4
1 2
2 4
4 5
5 6
5 7
3 4
1 7
1 4
2 2 4
1 1
*/
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
19288 KB |
Output is correct |
2 |
Incorrect |
45 ms |
20164 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
15 ms |
17500 KB |
Output is correct |
2 |
Correct |
16 ms |
17500 KB |
Output is correct |
3 |
Correct |
22 ms |
22148 KB |
Output is correct |
4 |
Correct |
28 ms |
20948 KB |
Output is correct |
5 |
Correct |
33 ms |
22484 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
14 ms |
18100 KB |
Output is correct |
2 |
Correct |
14 ms |
18104 KB |
Output is correct |
3 |
Correct |
37 ms |
29012 KB |
Output is correct |
4 |
Correct |
46 ms |
28748 KB |
Output is correct |
5 |
Correct |
32 ms |
29020 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1032 ms |
20824 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
48 ms |
22100 KB |
Output is correct |
2 |
Incorrect |
77 ms |
21916 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
63 ms |
23756 KB |
Output is correct |
2 |
Execution timed out |
1049 ms |
25940 KB |
Time limit exceeded |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
3 ms |
19288 KB |
Output is correct |
2 |
Incorrect |
45 ms |
20164 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |