#include <iostream>
#include <stack>
#include <string>
#include <queue>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <cassert>
using namespace std;
typedef long long ll;
const ll mod = 1e9 + 7;
vector<int> adj[202];
int dist[202][202];
bool vis[202];
int chk[202], n, k;
ll pw = 1;
int getDist(int root, int x, int p)
{
if(x == root)
{
int Fi = 0, Se = 0;
for(int i : adj[x])
{
dist[root][i] = 1;
Se = max(Se, getDist(root, i, x));
if(Se > Fi) swap(Se, Fi);
}
if(Fi + Se + 1 < k)
{
pw = (pw * 2)%mod;
chk[x] = x;
}
return 0;
}
int ret = dist[root][x];
for(int i : adj[x])
{
if(i == p) continue;
dist[root][i] = dist[root][x] + 1;
ret = max(ret, getDist(root, i, x));
}
return ret;
}
int tmp[202];
void dfs(int x, int p, int col)
{
vis[x] = true;
for(int i : adj[x])
{
if(i == p) continue;
if(chk[i] == col) continue;
tmp[i] = tmp[x] + 1;
dfs(i, x, col);
}
}
int getRadius(int x, int col)
{
if(chk[x] == col) return 0;
if(vis[x]) return 0;
for(int i=1;i<=n;i++) tmp[i] = 0;
dfs(x, -1, col);
int S = 1;
for(int i=1;i<=n;i++) if(tmp[S] < tmp[i]) S = i;
for(int i=1;i<=n;i++) tmp[i] = 0;
dfs(S, -1, col);
int ret = 0;
for(int i=1;i<=n;i++) ret = max(ret, tmp[i]);
return ret;
}
int main()
{
ios::sync_with_stdio(false); cin.tie(NULL);
cin >> n >> k;
for(int i=1;i<n;i++)
{
int u, v; cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
for(int i=1;i<=n;i++)
getDist(i, i, -1);
/*
for(int i=1;i<=n;i++)
{
for(int j=1;j<=n;j++)
{
cout << dist[i][j] << " ";
}
cout << "\n";
}
*/
ll ans = 0;
for(int i=1;i<=n;i++)
{
if(chk[i]) continue;
vector<int> v;
for(int j=1;j<=n;j++) if(dist[i][j]%k == 0)
{
v.push_back(j);
chk[j] = i;
}
bool flag = true;
for(int a : v) for(int b : v)
if(dist[a][b]%k != 0) flag = false;
int rad = 0;
for(int j=1;j<=n;j++) vis[j] = false;
for(int j=1;j<=n;j++)
rad = max(rad, getRadius(j, i));
if(rad >= k - 1) flag = false;
if(flag)
{
//cout << i << " ";
ans++;
}
}
//cout << "\n";
if(ans == 0) cout << "NO\n0";
else cout << "YES\n" << (ans * pw)%mod;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Partially correct |
0 ms |
212 KB |
Output is partially correct |
2 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
3 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
4 |
Correct |
2 ms |
468 KB |
Output is correct |
5 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
6 |
Partially correct |
3 ms |
468 KB |
Output is partially correct |
7 |
Correct |
3 ms |
468 KB |
Output is correct |
8 |
Correct |
2 ms |
468 KB |
Output is correct |
9 |
Correct |
2 ms |
468 KB |
Output is correct |
10 |
Correct |
2 ms |
468 KB |
Output is correct |
11 |
Incorrect |
3 ms |
468 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Partially correct |
0 ms |
212 KB |
Output is partially correct |
2 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
3 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
4 |
Correct |
2 ms |
468 KB |
Output is correct |
5 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
6 |
Partially correct |
3 ms |
468 KB |
Output is partially correct |
7 |
Correct |
3 ms |
468 KB |
Output is correct |
8 |
Correct |
2 ms |
468 KB |
Output is correct |
9 |
Correct |
2 ms |
468 KB |
Output is correct |
10 |
Correct |
2 ms |
468 KB |
Output is correct |
11 |
Incorrect |
3 ms |
468 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Partially correct |
0 ms |
212 KB |
Output is partially correct |
2 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
3 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
4 |
Correct |
2 ms |
468 KB |
Output is correct |
5 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
6 |
Partially correct |
3 ms |
468 KB |
Output is partially correct |
7 |
Correct |
3 ms |
468 KB |
Output is correct |
8 |
Correct |
2 ms |
468 KB |
Output is correct |
9 |
Correct |
2 ms |
468 KB |
Output is correct |
10 |
Correct |
2 ms |
468 KB |
Output is correct |
11 |
Incorrect |
3 ms |
468 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Partially correct |
0 ms |
212 KB |
Output is partially correct |
2 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
3 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
4 |
Correct |
2 ms |
468 KB |
Output is correct |
5 |
Partially correct |
2 ms |
468 KB |
Output is partially correct |
6 |
Partially correct |
3 ms |
468 KB |
Output is partially correct |
7 |
Correct |
3 ms |
468 KB |
Output is correct |
8 |
Correct |
2 ms |
468 KB |
Output is correct |
9 |
Correct |
2 ms |
468 KB |
Output is correct |
10 |
Correct |
2 ms |
468 KB |
Output is correct |
11 |
Incorrect |
3 ms |
468 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |