# include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
#define int long long
#define pii pair <int, int>
#define pb push_back
const int N = 3e5 + 5, mod = 1e9 + 7;
int t,n,a[N],fq[N],inv[N],cnt,r;
vector <int> v[N];
int f_p(int base, int power) {
int result = 1;
while (power > 0) {
if (power % 2) result = (result * base) % mod;
power /= 2;
base = (base * base) % mod;
}
return result;
}
int C(int n, int k) {
return (((fq[n] * inv[k])%mod) * inv[n - k]) % mod;
}
/*
*/
main() {
std::ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
cin>>n>>r;
fq[0] = 1;
for (int i = 1; i < N; i++) {
fq[i] = (fq[i - 1] * i)%mod;
}
inv[N - 1] = f_p(fq[N - 1], mod - 2);
for (int i = N - 2; i > 1; i--) {
inv[i] = (inv[i + 1] * (i + 1)) % mod;
}
inv[0] = 1;
for (int i = 1; i <= n - 1; i++) {
int a, b;
cin>>a>>b;
v[a].pb(b);
v[b].pb(a);
}
cnt = n;
for (int i = 1; i <= n; i++) {
if (v[i].size() != 1 || i == 1) {
// isn't leaf
cnt++;
v[i].pb(cnt);
v[cnt].pb(i);
}
}
n = cnt;
int lf = 0;
for (int i = 1; i <= n; i++) {
if (i != 1 && v[i].size() == 1) lf++;
}
int q;
cin>>q;
cout<<C(r + lf - 1, lf - 1)<<"\n";
/*
*/
}
Compilation message
Main.cpp:25:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
25 | main() {
| ^~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
108 ms |
49996 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
10 ms |
11984 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
110 ms |
50152 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
108 ms |
50924 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Runtime error |
108 ms |
49996 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |