#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
const int maxn = 5e5+10;
const int mod = 1e9+7;
int n, d;
vector<pair<int,int>> g[maxn];
void solve() {
cin >> n >> d;
for(int i = 1; i <= n-1; i++) {
int u,v; cin >> u >> v;
int idu = g[u].size();
int idv = g[v].size();
g[u].pb(mp(v,idv));
g[v].pb(mp(u,idu));
}
int ans = 1;
int x = 2;
for(int i = 0; i <= 61; i++) {
if((1LL<<i)&(2*d)) {
ans*= x;
ans%= mod;
}
x*= x;
x%= mod;
}
cout << ans << endl;
}
int32_t main() {
ios::sync_with_stdio(false); cin.tie(0);
// freopen("in.in", "r", stdin);
// freopen("out.out", "w", stdout);
int tt = 1;
// cin >> tt;
while(tt--) {
solve();
}
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11988 KB |
Output is correct |
2 |
Incorrect |
7 ms |
12116 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11996 KB |
Output is correct |
2 |
Correct |
8 ms |
11940 KB |
Output is correct |
3 |
Correct |
7 ms |
11988 KB |
Output is correct |
4 |
Correct |
8 ms |
12008 KB |
Output is correct |
5 |
Correct |
7 ms |
12116 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11988 KB |
Output is correct |
2 |
Incorrect |
6 ms |
11988 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11988 KB |
Output is correct |
2 |
Incorrect |
6 ms |
11988 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11988 KB |
Output is correct |
2 |
Incorrect |
6 ms |
11988 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11988 KB |
Output is correct |
2 |
Incorrect |
6 ms |
11988 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11988 KB |
Output is correct |
2 |
Incorrect |
6 ms |
11988 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
6 ms |
11988 KB |
Output is correct |
2 |
Incorrect |
7 ms |
12116 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |