// #pragma GCC optimize("Ofast")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
// #pragma GCC optimize("unroll-loops")
#include "bits/stdc++.h"
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/trie_policy.hpp>
// #include <ext/rope>
using namespace std;
// using namespace __gnu_pbds;
// using namespace __gnu_cxx;
#define li long long
#define ld long double
#define ii pair<int, int>
#define vi vector<int>
#define vvi vector<vi>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pf push_front
#define eb emplace_back
#define em emplace
#define ob pop_back
#define om pop
#define of pop_front
#define fr front
#define bc back
#define fori(i, a, b) for(int i = (int) (a); i <= (int) (b); ++i)
#define ford(i, a, b) for(int i = (int) (a); i >= (int) (b); --i)
#define all(x) begin(x), end(x)
#define sz(x) ((int)(x).size())
#define bitc __builtin_popcountll
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define rand rng
#define endl '\n'
#define sp ' '
#define fastio() ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define forIT(it, begin, end) for(__typeof(end) it = (begin) - ((begin) > (end)); it != (end) - ((begin) > (end)); it += 1 - 2 * ((begin) > (end)) )
void solve();
signed main() {
// freopen("test.inp", "r", stdin);
// fastio();
int tc = 1;
// cin >> tc;
fori(test, 1, tc) {
solve();
}
return 0;
}
#define int long long
const ld pi = 4 * atan(1.0), eps = 1e-9;
const int maxn = 4000 + 5, inf = LLONG_MAX / 100ll, mod = 1e9 + 7;
int n, m;
int fac[maxn];
int inv_fac[maxn];
int bp(int i, int p) {
int r = 1;
while(p) {
if(p & 1) r = r * i % mod;
i = i * i % mod;
p >>= 1;
}
return r;
}
int C(int n, int k) {
if(k < 0 or k > n) return 0;
return fac[n] * inv_fac[n - k] % mod * inv_fac[k] % mod;
}
int dp[maxn][maxn];
int w[maxn];
void solve() {
cin >> n >> m;
fac[0] = inv_fac[0] = 1;
fori(i,1,2 * n) {
fac[i] = fac[i - 1] * i % mod;
inv_fac[i] = bp(fac[i], mod -2);
}
fori(i, 0, m - 1) {
int num = 2 * n / m + (i < 2 * n % m);
// cout << i << sp << num << sp << endl;
fori(used, 0, n) {
fori(tran, 0, num / 2) {
(dp[i][used + tran] += (i? dp[i - 1][used]: used == 0) * C(tran + used, tran) % mod * fac[num] % mod * inv_fac[num - 2 * tran] % mod) %= mod;
}
}
// fori(used, 0, n) {
// cout << i << sp << used << sp << dp[i][used] << endl;
// }
}
// cout << C(2, 1) << endl;
int ans = 0;
fori(i, 0, n) {
w[i] = dp[m - 1][i] * fac[2 * n - 2 * i] % mod; //cout << i << sp << w[i] << endl;
(ans += w[i] * C(n, i) * bp(-1, i) % mod) %= mod;
}
cout << ans;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
224 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
332 KB |
Output is correct |
5 |
Correct |
0 ms |
296 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
1 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 ms |
332 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
224 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
332 KB |
Output is correct |
5 |
Correct |
0 ms |
296 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
1 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 ms |
332 KB |
Output is correct |
11 |
Correct |
1 ms |
560 KB |
Output is correct |
12 |
Correct |
1 ms |
460 KB |
Output is correct |
13 |
Incorrect |
0 ms |
332 KB |
Output isn't correct |
14 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
224 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
332 KB |
Output is correct |
5 |
Correct |
0 ms |
296 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
1 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 ms |
332 KB |
Output is correct |
11 |
Correct |
1 ms |
560 KB |
Output is correct |
12 |
Correct |
1 ms |
460 KB |
Output is correct |
13 |
Incorrect |
0 ms |
332 KB |
Output isn't correct |
14 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
224 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
332 KB |
Output is correct |
5 |
Correct |
0 ms |
296 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
1 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 ms |
332 KB |
Output is correct |
11 |
Correct |
1 ms |
560 KB |
Output is correct |
12 |
Correct |
1 ms |
460 KB |
Output is correct |
13 |
Incorrect |
0 ms |
332 KB |
Output isn't correct |
14 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
204 KB |
Output is correct |
2 |
Correct |
1 ms |
224 KB |
Output is correct |
3 |
Correct |
0 ms |
204 KB |
Output is correct |
4 |
Correct |
0 ms |
332 KB |
Output is correct |
5 |
Correct |
0 ms |
296 KB |
Output is correct |
6 |
Correct |
0 ms |
204 KB |
Output is correct |
7 |
Correct |
1 ms |
204 KB |
Output is correct |
8 |
Correct |
0 ms |
204 KB |
Output is correct |
9 |
Correct |
0 ms |
204 KB |
Output is correct |
10 |
Correct |
0 ms |
332 KB |
Output is correct |
11 |
Correct |
1 ms |
560 KB |
Output is correct |
12 |
Correct |
1 ms |
460 KB |
Output is correct |
13 |
Incorrect |
0 ms |
332 KB |
Output isn't correct |
14 |
Halted |
0 ms |
0 KB |
- |