#include<bits/stdc++.h>
#define ff first
#define ss second
#define all(x) x.begin(), x.end()
using namespace std;
using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
template<typename T>
using matrix = vector<vector<T>>;
const int MOD = 1e9+7;
const int INF = 1e9;
int main(){
cin.tie(0)->sync_with_stdio(0);
int n, k;
cin >> n >> k;
if(n > 10000)
return 0;
k--;
matrix<int> g(n+1);
for(int i = 1; i < n; i++){
int a, b;
cin >> a >> b;
g[a].push_back(b);
g[b].push_back(a);
}
vector<ll> power(n+1);
power[0] = 1;
for(int i = 1; i <= n; i++)
power[i] = power[i-1]*2%MOD;
vector<int> d(n+1), d2(n+1);
auto getd =[&](int id, int last, vector<int>& D, auto dfs) -> void {
for(int i : g[id]){
if(i != last){
D[i] = D[id]+1;
dfs(i,id,D,dfs);
}
}
};
getd(1,0,d,getd);
int ponta = 1;
for(int i = 2; i <= n; i++){
ponta = min(ponta,i,[&](int a, int b){
return d[a] > d[b];
});
}
getd(ponta,0,d2,getd);
ponta = 1;
for(int i = 2; i <= n; i++){
ponta = min(ponta,i,[&](int a, int b){
return d2[a] > d2[b];
});
}
fill(all(d),0);
getd(ponta,0,d,getd);
vector<int> dead(n+1);
vector<int> deg(n+1);
vector<int> st;
for(int i = 1; i <= n; i++){
deg[i] = g[i].size();
if(deg[i] == 1)
st.push_back(i);
}
while(!st.empty()){
int cur = st.back();
st.pop_back();
if(d[cur] >= k || d2[cur] >= k)
continue;
dead[cur] = 1;
for(int i : g[cur]){
deg[i]--;
if(deg[i] == 1)
st.push_back(i);
}
}
ll resp = power[accumulate(all(dead),0)];
if(accumulate(all(dead),0) == n){
cout << "YES\n";
cout << resp << '\n';
return 0;
}
matrix<int> g2(n+1);
for(int i = 1; i <= n; i++){
if(dead[i])
continue;
for(int j : g[i]){
if(!dead[j])
g2[i].push_back(j);
}
}
g.swap(g2);
k++;
vector<int> starts;
vector<int> startid(n+1,-1);
for(int i = 0; i < k; i++){
starts.push_back(ponta);
sort(all(g[ponta]), [&](int a, int b){
return d2[a] > d2[b];
});
startid[ponta] = i;
ponta = g[ponta].back(); // menor distancia pra outra ponta
}
vector<int> marc(n+1);
auto dfs =[&](int id, int last, int depth, auto dfs) -> void {
marc[id] = depth%k == 0;
for(int i : g[id])
if(i != last)
dfs(i,id,depth+1,dfs);
};
auto check =[&](int id, int last, int depth, int choosen, auto dfs) -> bool {
choosen+=marc[id];
if(depth == k-1){
return choosen == 1;
}
bool ret = 1;
for(int i : g[id]){
if(i!=last)
ret&=dfs(i,id,depth+1,choosen,dfs);
}
return ret;
};
int ct = 0;
for(int start : starts){
fill(all(marc),0);
dfs(start,-1,0,dfs);
bool ok = 1;
for(int i = 1; i <= n; i++){
if(!dead[i])
ok&=check(i,-1,0,0,check);
}
// cerr << "->" << start << ' ' << ct << '\n';
ct+=ok;
}
if(ct){
cout << "YES\n";
} else cout << "NO\n";
cout << resp*ct%MOD << '\n';
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Partially correct |
10 ms |
340 KB |
Output is partially correct |
3 |
Partially correct |
19 ms |
340 KB |
Output is partially correct |
4 |
Correct |
4 ms |
340 KB |
Output is correct |
5 |
Partially correct |
10 ms |
340 KB |
Output is partially correct |
6 |
Partially correct |
9 ms |
344 KB |
Output is partially correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
1 ms |
340 KB |
Output is correct |
9 |
Correct |
1 ms |
340 KB |
Output is correct |
10 |
Correct |
3 ms |
340 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
0 ms |
212 KB |
Output is correct |
13 |
Correct |
1 ms |
340 KB |
Output is correct |
14 |
Correct |
5 ms |
340 KB |
Output is correct |
15 |
Correct |
9 ms |
340 KB |
Output is correct |
16 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
17 |
Partially correct |
4 ms |
340 KB |
Output is partially correct |
18 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
19 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
20 |
Correct |
4 ms |
340 KB |
Output is correct |
21 |
Partially correct |
3 ms |
340 KB |
Output is partially correct |
22 |
Partially correct |
8 ms |
340 KB |
Output is partially correct |
23 |
Partially correct |
15 ms |
344 KB |
Output is partially correct |
24 |
Partially correct |
13 ms |
344 KB |
Output is partially correct |
25 |
Correct |
5 ms |
340 KB |
Output is correct |
26 |
Correct |
3 ms |
340 KB |
Output is correct |
27 |
Correct |
6 ms |
340 KB |
Output is correct |
28 |
Correct |
6 ms |
344 KB |
Output is correct |
29 |
Correct |
1 ms |
340 KB |
Output is correct |
30 |
Correct |
3 ms |
340 KB |
Output is correct |
31 |
Correct |
2 ms |
340 KB |
Output is correct |
32 |
Correct |
1 ms |
340 KB |
Output is correct |
33 |
Correct |
1 ms |
340 KB |
Output is correct |
34 |
Correct |
1 ms |
340 KB |
Output is correct |
35 |
Correct |
1 ms |
340 KB |
Output is correct |
36 |
Partially correct |
3 ms |
340 KB |
Output is partially correct |
37 |
Correct |
8 ms |
344 KB |
Output is correct |
38 |
Correct |
8 ms |
344 KB |
Output is correct |
39 |
Correct |
5 ms |
348 KB |
Output is correct |
40 |
Correct |
3 ms |
340 KB |
Output is correct |
41 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
42 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Partially correct |
10 ms |
340 KB |
Output is partially correct |
3 |
Partially correct |
19 ms |
340 KB |
Output is partially correct |
4 |
Correct |
4 ms |
340 KB |
Output is correct |
5 |
Partially correct |
10 ms |
340 KB |
Output is partially correct |
6 |
Partially correct |
9 ms |
344 KB |
Output is partially correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
1 ms |
340 KB |
Output is correct |
9 |
Correct |
1 ms |
340 KB |
Output is correct |
10 |
Correct |
3 ms |
340 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
0 ms |
212 KB |
Output is correct |
13 |
Correct |
1 ms |
340 KB |
Output is correct |
14 |
Correct |
5 ms |
340 KB |
Output is correct |
15 |
Correct |
9 ms |
340 KB |
Output is correct |
16 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
17 |
Partially correct |
4 ms |
340 KB |
Output is partially correct |
18 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
19 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
20 |
Correct |
4 ms |
340 KB |
Output is correct |
21 |
Partially correct |
3 ms |
340 KB |
Output is partially correct |
22 |
Partially correct |
8 ms |
340 KB |
Output is partially correct |
23 |
Partially correct |
15 ms |
344 KB |
Output is partially correct |
24 |
Partially correct |
13 ms |
344 KB |
Output is partially correct |
25 |
Correct |
5 ms |
340 KB |
Output is correct |
26 |
Correct |
3 ms |
340 KB |
Output is correct |
27 |
Correct |
6 ms |
340 KB |
Output is correct |
28 |
Correct |
6 ms |
344 KB |
Output is correct |
29 |
Correct |
1 ms |
340 KB |
Output is correct |
30 |
Correct |
3 ms |
340 KB |
Output is correct |
31 |
Correct |
2 ms |
340 KB |
Output is correct |
32 |
Correct |
1 ms |
340 KB |
Output is correct |
33 |
Correct |
1 ms |
340 KB |
Output is correct |
34 |
Correct |
1 ms |
340 KB |
Output is correct |
35 |
Correct |
1 ms |
340 KB |
Output is correct |
36 |
Partially correct |
3 ms |
340 KB |
Output is partially correct |
37 |
Correct |
8 ms |
344 KB |
Output is correct |
38 |
Correct |
8 ms |
344 KB |
Output is correct |
39 |
Correct |
5 ms |
348 KB |
Output is correct |
40 |
Correct |
3 ms |
340 KB |
Output is correct |
41 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
42 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Partially correct |
10 ms |
340 KB |
Output is partially correct |
3 |
Partially correct |
19 ms |
340 KB |
Output is partially correct |
4 |
Correct |
4 ms |
340 KB |
Output is correct |
5 |
Partially correct |
10 ms |
340 KB |
Output is partially correct |
6 |
Partially correct |
9 ms |
344 KB |
Output is partially correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
1 ms |
340 KB |
Output is correct |
9 |
Correct |
1 ms |
340 KB |
Output is correct |
10 |
Correct |
3 ms |
340 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
0 ms |
212 KB |
Output is correct |
13 |
Correct |
1 ms |
340 KB |
Output is correct |
14 |
Correct |
5 ms |
340 KB |
Output is correct |
15 |
Correct |
9 ms |
340 KB |
Output is correct |
16 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
17 |
Partially correct |
4 ms |
340 KB |
Output is partially correct |
18 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
19 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
20 |
Correct |
4 ms |
340 KB |
Output is correct |
21 |
Partially correct |
3 ms |
340 KB |
Output is partially correct |
22 |
Partially correct |
8 ms |
340 KB |
Output is partially correct |
23 |
Partially correct |
15 ms |
344 KB |
Output is partially correct |
24 |
Partially correct |
13 ms |
344 KB |
Output is partially correct |
25 |
Correct |
5 ms |
340 KB |
Output is correct |
26 |
Correct |
3 ms |
340 KB |
Output is correct |
27 |
Correct |
6 ms |
340 KB |
Output is correct |
28 |
Correct |
6 ms |
344 KB |
Output is correct |
29 |
Correct |
1 ms |
340 KB |
Output is correct |
30 |
Correct |
3 ms |
340 KB |
Output is correct |
31 |
Correct |
2 ms |
340 KB |
Output is correct |
32 |
Correct |
1 ms |
340 KB |
Output is correct |
33 |
Correct |
1 ms |
340 KB |
Output is correct |
34 |
Correct |
1 ms |
340 KB |
Output is correct |
35 |
Correct |
1 ms |
340 KB |
Output is correct |
36 |
Partially correct |
3 ms |
340 KB |
Output is partially correct |
37 |
Correct |
8 ms |
344 KB |
Output is correct |
38 |
Correct |
8 ms |
344 KB |
Output is correct |
39 |
Correct |
5 ms |
348 KB |
Output is correct |
40 |
Correct |
3 ms |
340 KB |
Output is correct |
41 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
42 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Partially correct |
10 ms |
340 KB |
Output is partially correct |
3 |
Partially correct |
19 ms |
340 KB |
Output is partially correct |
4 |
Correct |
4 ms |
340 KB |
Output is correct |
5 |
Partially correct |
10 ms |
340 KB |
Output is partially correct |
6 |
Partially correct |
9 ms |
344 KB |
Output is partially correct |
7 |
Correct |
1 ms |
340 KB |
Output is correct |
8 |
Correct |
1 ms |
340 KB |
Output is correct |
9 |
Correct |
1 ms |
340 KB |
Output is correct |
10 |
Correct |
3 ms |
340 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
0 ms |
212 KB |
Output is correct |
13 |
Correct |
1 ms |
340 KB |
Output is correct |
14 |
Correct |
5 ms |
340 KB |
Output is correct |
15 |
Correct |
9 ms |
340 KB |
Output is correct |
16 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
17 |
Partially correct |
4 ms |
340 KB |
Output is partially correct |
18 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
19 |
Partially correct |
5 ms |
340 KB |
Output is partially correct |
20 |
Correct |
4 ms |
340 KB |
Output is correct |
21 |
Partially correct |
3 ms |
340 KB |
Output is partially correct |
22 |
Partially correct |
8 ms |
340 KB |
Output is partially correct |
23 |
Partially correct |
15 ms |
344 KB |
Output is partially correct |
24 |
Partially correct |
13 ms |
344 KB |
Output is partially correct |
25 |
Correct |
5 ms |
340 KB |
Output is correct |
26 |
Correct |
3 ms |
340 KB |
Output is correct |
27 |
Correct |
6 ms |
340 KB |
Output is correct |
28 |
Correct |
6 ms |
344 KB |
Output is correct |
29 |
Correct |
1 ms |
340 KB |
Output is correct |
30 |
Correct |
3 ms |
340 KB |
Output is correct |
31 |
Correct |
2 ms |
340 KB |
Output is correct |
32 |
Correct |
1 ms |
340 KB |
Output is correct |
33 |
Correct |
1 ms |
340 KB |
Output is correct |
34 |
Correct |
1 ms |
340 KB |
Output is correct |
35 |
Correct |
1 ms |
340 KB |
Output is correct |
36 |
Partially correct |
3 ms |
340 KB |
Output is partially correct |
37 |
Correct |
8 ms |
344 KB |
Output is correct |
38 |
Correct |
8 ms |
344 KB |
Output is correct |
39 |
Correct |
5 ms |
348 KB |
Output is correct |
40 |
Correct |
3 ms |
340 KB |
Output is correct |
41 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
42 |
Halted |
0 ms |
0 KB |
- |