#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
typedef long long ll;
const int maxn = 1e5 + 10;
int n, q;
vector < int > adj[maxn];
void input()
{
cin >> n >> q;
for (int i = 1; i < n; i ++)
{
int v, u;
cin >> v >> u;
adj[v].push_back(u);
adj[u].push_back(v);
}
}
int find_leaves(int v, int par)
{
int cnt = 0, children = 0;
for (int u : adj[v])
{
if (u == par)
continue;
cnt += find_leaves(u, v);
children ++;
}
if (par == -1 && children == 1)
cnt ++;
if (children == 0)
cnt ++;
return cnt;
}
int sub[maxn], parent[maxn], is_leaf[maxn];
int tin[maxn], tout[maxn], timer, occ[2 * maxn];
ll depth[maxn];
void calc(int v, int par)
{
occ[++ timer] = v;
tin[v] = timer;
sub[v] = 1;
parent[v] = par;
is_leaf[v] = true;
for (int u : adj[v])
{
if (u == par)
continue;
is_leaf[v] = false;
depth[u] = depth[v] + 1;
calc(u, v);
sub[v] += sub[u];
occ[++ timer] = v;
}
tout[v] = timer;
}
const int maxlog = 21;
int dp[maxlog][maxn * 2], lg[2 * maxn];
void build_sparse_table()
{
for (int i = 1; i <= timer; i ++)
{
lg[i] = lg[i / 2] + 1;
dp[0][i] = occ[i];
}
for (int j = 1; j < maxlog; j ++)
for (int i = 1; i <= (n - (1 << j)) + 1; i ++)
{
dp[j][i] = dp[j - 1][i + (1 << (j - 1))];
if (depth[dp[j - 1][i]] < depth[dp[j][i]])
dp[j][i] = dp[j - 1][i];
}
}
int get_lca(int v, int u)
{
int l = tin[v], r = tin[u];
if (l > r)
swap(l, r);
int len = lg[r - l + 1] - 1, lca = dp[len][r - (1 << len) + 1];
if (depth[dp[len][l]] < depth[lca])
lca = dp[len][l];
return lca;
}
ll get_distance(int v, int u)
{
return depth[v] + depth[u] - 2 * depth[get_lca(v, u)];
}
int find_centroid(int v, int par, int sz)
{
for (int u : adj[v])
{
if (u == par)
continue;
if (sub[u] > sz / 2)
{
return find_centroid(u, v, sz);
}
}
return v;
}
ll added[maxn];
ll sum[maxn], cnt[maxn];
int all = 0;
void find_depths(int v)
{
all ++;
sum[v] = cnt[v] = 0;
bool leaf = true;
for (int u : adj[v])
{
if (u == parent[v])
continue;
find_depths(u);
cnt[v] += cnt[u];
sum[v] += sum[u];
leaf = false;
}
sum[v] = sum[v] + added[v] * (depth[v] + 1);
cnt[v] += added[v];
if (leaf && added[v] == 0)
sum[v] = sum[v] + depth[v], cnt[v] ++;
ll pairs = cnt[v] / 2;
if (pairs * 2 == cnt[v])
pairs --;
sum[v] = sum[v] - pairs * depth[v] * (ll)2;
cnt[v] -= pairs * 2;
added[v] = 0;
//cout << "state " << v << " " << cnt_leaves << " " << ans << endl;
}
int used[maxn];
void answer_queries()
{
int root = 1;
while(adj[root].size() == 1)
root ++;
calc(root, -1);
build_sparse_table();
for (int i = 1; i <= q; i ++)
{
int d;
cin >> d;
for (int j = 1; j <= d; j ++)
{
int par;
cin >> par;
added[par] ++;
}
if (n <= 20000 && q <= 300)
find_depths(root);
if (cnt[root] % 2 == 1)
cout << -1 << endl;
else
cout << sum[root] << endl;
}
}
void solve()
{
input();
answer_queries();
}
void speed()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}
int main()
{
speed();
solve();
return 0;
}
/**
7 3
1 2
2 4
4 5
5 6
5 7
3 4
1 4
2 2 4
1 1
3 1
1 2
1 3
6 3 3 3 2 2 2
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
7516 KB |
Output is correct |
2 |
Incorrect |
14 ms |
17552 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
7 ms |
13912 KB |
Output is correct |
2 |
Correct |
7 ms |
13912 KB |
Output is correct |
3 |
Incorrect |
25 ms |
26312 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
8 ms |
16472 KB |
Output is correct |
2 |
Correct |
8 ms |
16476 KB |
Output is correct |
3 |
Incorrect |
33 ms |
33420 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
190 ms |
18008 KB |
Output is correct |
2 |
Correct |
131 ms |
17244 KB |
Output is correct |
3 |
Correct |
196 ms |
17240 KB |
Output is correct |
4 |
Correct |
227 ms |
18012 KB |
Output is correct |
5 |
Correct |
188 ms |
18012 KB |
Output is correct |
6 |
Correct |
233 ms |
18000 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
31 ms |
23360 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
57 ms |
24912 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
7516 KB |
Output is correct |
2 |
Incorrect |
14 ms |
17552 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |