// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
using namespace std;
#define nl '\n'
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
template<class T> using V = vector<T>;
using vi = V<int>;
using pi = pair<int, int>;
using ll = long long;
using vl = V<ll>;
const int LG = 20;
int main() {
cin.tie(0)->sync_with_stdio(0);
int N, Q; cin >> N >> Q;
V<vi> adj(N); for(int i = 0; i < N - 1; i++) {
int u, v; cin >> u >> v; --u, --v;
adj[u].pb(v);
adj[v].pb(u);
}
int R = -1; for(int i = 0; i < N; i++) if (sz(adj[i]) > 1) {
R = i;
break;
}
V<vi> C(2, vi(N)); vi L(N), st(N), en(N); int t = 0;
V<vi> up(N, vi(LG)); vi dep(N);
auto jmp = [&](int u, int d) {
for(int i = 0; i < LG; i++) if ((d >> i) & 1) u = up[u][i];
return u;
};
auto lca = [&](int a, int b) {
if (dep[a] < dep[b]) swap(a, b);
a = jmp(a, dep[a] - dep[b]);
if (a == b) return a;
for(int i = LG - 1; i >= 0; i--) {
if (up[a][i] != up[b][i]) {
a = up[a][i];
b = up[b][i];
}
}
return up[a][0];
};
function<void(int, int)> gen = [&](int u, int p) {
up[u][0] = p; dep[u] = (u == p ? 0 : dep[p] + 1);
for(int i = 1; i < LG; i++) up[u][i] = up[up[u][i-1]][i-1];
st[u] = t++;
for(auto& v : adj[u]) if (v != p) {
gen(v, u); L[u] += L[v];
}
en[u] = t - 1;
if (st[u] == en[u]) L[u] = 1;
};
gen(R, R);
int ex = 0;
function<void(int, int)> dfs = [&](int u, int p) {
C[L[u] & 1][u]++;
if (L[u] % 2 == 0) ex++;
for(auto& v : adj[u]) if (v != p) {
C[0][v] += C[0][u];
C[1][v] += C[1][u];
dfs(v, u);
}
};
dfs(R, -1);
int leaves = L[R];
vi F(N, 0), seen(N, 0);
for(int i = 0; i < Q; i++) {
int K; cin >> K;
vi D(K); for(auto& x : D) { cin >> x; --x; }
vi S;
for(auto x : D) {
if (st[x] == en[x]) {
if (seen[x]) { S.pb(x); F[x]++; }
else seen[x] = 1;
} else {
S.pb(x);
F[x]++;
}
}
if ((leaves + sz(S)) & 1) {
for(auto& x : S) F[x] = 0;
for(auto& x : D) seen[x] = 0;
cout << -1 << nl;
continue;
}
if (sz(S) == 0) {
for(auto& x : S) F[x] = 0;
for(auto& x : D) seen[x] = 0;
cout << (N - 1) + ex << nl;
continue;
}
int ans = ex;
sort(begin(S), end(S), [&](int x, int y) { return st[x] < st[y]; });
int M = sz(S);
for(int x = 0; x < M - 1; x++) {
int l = lca(S[x], S[x + 1]); S.pb(l);
}
sort(begin(S), end(S), [&](int x, int y) { return st[x] < st[y]; });
S.erase(unique(begin(S), end(S)), end(S));
M = sz(S);
vi stk = {-1}; V<vi> chd(M);
int rt = -1;
for(int u = 0; u < M; u++) {
while(stk.back() != -1 && en[S[stk.back()]] < st[S[u]]) stk.pop_back();
int p = stk.back();
if (p != -1) chd[p].pb(u);
else rt = u;
stk.pb(u);
}
function<void(int, int)> upd = [&](int u, int p) {
for(auto& v : chd[u]) {
upd(v, u);
F[S[u]] += F[S[v]];
}
if (F[S[u]] & 1) {
ans -= C[0][S[u]]; ans += C[1][S[u]];
if (p != -1) { ans -= C[1][S[p]]; ans += C[0][S[p]]; }
}
};
if (rt != -1) upd(rt, -1);
for(auto& x : S) F[x] = 0;
for(auto& x : D) seen[x] = 0;
cout << (N + K) - 1 + ans - 1 << nl;
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
32 ms |
4660 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
18 ms |
2380 KB |
Output is correct |
2 |
Correct |
6 ms |
1872 KB |
Output is correct |
3 |
Correct |
52 ms |
21004 KB |
Output is correct |
4 |
Correct |
48 ms |
16224 KB |
Output is correct |
5 |
Correct |
70 ms |
22468 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
24 ms |
3216 KB |
Output is correct |
2 |
Correct |
7 ms |
2768 KB |
Output is correct |
3 |
Correct |
68 ms |
29944 KB |
Output is correct |
4 |
Correct |
89 ms |
31372 KB |
Output is correct |
5 |
Correct |
56 ms |
27024 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
32 ms |
5284 KB |
Output is correct |
2 |
Correct |
17 ms |
4572 KB |
Output is correct |
3 |
Correct |
10 ms |
4308 KB |
Output is correct |
4 |
Correct |
12 ms |
5092 KB |
Output is correct |
5 |
Correct |
13 ms |
5260 KB |
Output is correct |
6 |
Correct |
27 ms |
5188 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
62 ms |
14044 KB |
Output is correct |
2 |
Incorrect |
65 ms |
13784 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
102 ms |
21228 KB |
Output is correct |
2 |
Correct |
118 ms |
24448 KB |
Output is correct |
3 |
Correct |
126 ms |
24568 KB |
Output is correct |
4 |
Correct |
109 ms |
23876 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
32 ms |
4660 KB |
Output is correct |
3 |
Correct |
18 ms |
2380 KB |
Output is correct |
4 |
Correct |
6 ms |
1872 KB |
Output is correct |
5 |
Correct |
52 ms |
21004 KB |
Output is correct |
6 |
Correct |
48 ms |
16224 KB |
Output is correct |
7 |
Correct |
70 ms |
22468 KB |
Output is correct |
8 |
Correct |
24 ms |
3216 KB |
Output is correct |
9 |
Correct |
7 ms |
2768 KB |
Output is correct |
10 |
Correct |
68 ms |
29944 KB |
Output is correct |
11 |
Correct |
89 ms |
31372 KB |
Output is correct |
12 |
Correct |
56 ms |
27024 KB |
Output is correct |
13 |
Correct |
32 ms |
5284 KB |
Output is correct |
14 |
Correct |
17 ms |
4572 KB |
Output is correct |
15 |
Correct |
10 ms |
4308 KB |
Output is correct |
16 |
Correct |
12 ms |
5092 KB |
Output is correct |
17 |
Correct |
13 ms |
5260 KB |
Output is correct |
18 |
Correct |
27 ms |
5188 KB |
Output is correct |
19 |
Correct |
62 ms |
14044 KB |
Output is correct |
20 |
Incorrect |
65 ms |
13784 KB |
Output isn't correct |
21 |
Halted |
0 ms |
0 KB |
- |