#include <bits/stdc++.h>
using namespace std;
const int MAXN = 100001;
struct Node {
int s = 0;
int cnt = 0;
};
vector<int> g[MAXN];
int depth[MAXN], parent[MAXN], pos[MAXN], head[MAXN], heavy[MAXN], timer = 0, n, q, leaf[MAXN];
Node tree[2 * MAXN];
void build(int u) {
while (u > 1) {
u /= 2;
tree[u].s = tree[2*u].s + tree[2*u+1].s;
}
}
void build() {
for (int i = 2 * n; i > n; i--) {
tree[i].cnt = 1;
}
for (int i = n; i >= 1; i--) {
tree[i].cnt = tree[2*i].cnt + tree[2*i+1].cnt;
}
}
void apply(int u) {
tree[u].s = (tree[u].cnt - tree[u].s);
}
int dfs(int u, int d) {
depth[u] = d;
int s = 1, max_s = 0;
for (int v : g[u]) {
if (v != parent[u]) {
parent[v] = u;
int k = dfs(v, d + 1);
s += k;
if (k > max_s) {
max_s = k;
heavy[u] = v;
}
}
}
return s;
}
void decomp(int u, int h) {
head[u] = h;
pos[u] = ++timer;
if (heavy[u])
decomp(heavy[u], h);
for (int v : g[u]) {
if (v != parent[u] && v != heavy[u])
decomp(v, v);
}
}
int qry() {
return tree[1].cnt-tree[1].s;
}
void segupd(int l, int r) {
l += n; r += n;
int a = l, b = r;
while (l <= r) {
if (l % 2 == 1) apply(l++);
if (r % 2 == 0) apply(r--);
l /= 2; r /= 2;
}
for (int i = 1; i <= n; i++) build(i+n);
build(a);
build(b);
}
void upd(int a, int b) {
for (; head[a] != head[b]; b = parent[head[b]]) {
if (depth[head[a]] > depth[head[b]])
swap(a, b);
segupd(pos[head[b]], pos[b]);
}
if (depth[a] > depth[b])
swap(a, b);
segupd(pos[a], pos[b]);
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
cin >> n >> q;
for (int i = 0; i < n - 1; i++) {
int a, b; cin >> a >> b;
g[a].push_back(b);
g[b].push_back(a);
}
dfs(1, 0);
decomp(1, 1);
build();
int leaves = 0;
for (int i = 1; i <= n; i++) {
leaf[i] = g[i].size() == 1;
if (leaf[i]) {
upd(1, i);
leaves++;
}
}
while (q--) {
int c; cin >> c;
vector<int> v(c);
for (int i = 0; i < c; i++) {
cin >> v[i];
if (leaf[v[i]] == 1) {
leaf[v[i]] = 2;
} else {
upd(1, v[i]);
leaves++;
}
}
if (leaves % 2 == 1) {
cout << "-1\n";
} else {
cout << n - 2 + c + qry() << "\n";
}
for (int i = 0; i < c; i++) {
if (leaf[v[i]] == 2) {
leaf[v[i]] = 1;
} else {
upd(1, v[i]);
leaves--;
}
}
}
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2644 KB |
Output is correct |
2 |
Execution timed out |
1088 ms |
4060 KB |
Time limit exceeded |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1075 ms |
3168 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1078 ms |
3668 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1063 ms |
4760 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1068 ms |
6976 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1072 ms |
9424 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
2644 KB |
Output is correct |
2 |
Execution timed out |
1088 ms |
4060 KB |
Time limit exceeded |
3 |
Halted |
0 ms |
0 KB |
- |