#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
#define fi first
#define se second
#define mp make_pair
#define fastIO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
const int N = 2005;
const int M = N * 2;
const int MOD = (int)1e9 + 7;
int mult(int x, int y){
return (x * 1ll * y) % MOD;
}
void add(int &u, int v){
u = (u + v) % MOD;
}
int pick[M][M];
int cnt[M];
int fac[M];
int dp[N][N];
int main(){
fastIO;
int n, m;
cin >> n >> m;
for(int i = 0 ; i < n * 2; i ++ ){
cnt[i % m] ++ ;
}
for(int i = 0 ; i < M; i ++ ){
pick[i][0]=1;
}
for(int i = 1; i < M; i ++ ){
for(int j = 1; j <= i; j ++ ){
add(pick[i][j], pick[i-1][j]);
add(pick[i][j], pick[i-1][j-1]);
}
}
fac[0] = 1;
for(int i = 1; i < M; i ++ ){
fac[i] = mult(fac[i - 1], i);
}
dp[0][0] = mult(pick[n][cnt[0]], fac[cnt[0]]);
int total = 0;
int single;
int value;
for(int i = 1; i < m ; i ++ ){
total += cnt[i - 1];
for(int j = 0 ; j <= n; j ++ ){
if(dp[i-1][j] == 0) continue;
for(int nx = 0; nx <= cnt[i]; nx ++ ){
single = total - 2ll * j;
if(single < 0) continue;
if(nx > single) continue;
if(single + j > n) continue;
if(j + nx > n) continue;
value = dp[i - 1][j];
value = mult(value, pick[single][nx]);
value = mult(value, pick[n - single - j][cnt[i] - nx]);
value = mult(value, fac[cnt[i]]);
add(dp[i][j + nx], value);
}
}
}
int sol = dp[m-1][n];
for(int i = 1; i <= n; i ++ ){
sol = mult(sol, 2);
}
cout << sol << "\n";
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
55 ms |
45820 KB |
Output is correct |
2 |
Correct |
49 ms |
45744 KB |
Output is correct |
3 |
Correct |
49 ms |
45820 KB |
Output is correct |
4 |
Correct |
50 ms |
45720 KB |
Output is correct |
5 |
Correct |
49 ms |
45772 KB |
Output is correct |
6 |
Correct |
47 ms |
45832 KB |
Output is correct |
7 |
Correct |
58 ms |
45768 KB |
Output is correct |
8 |
Correct |
47 ms |
45792 KB |
Output is correct |
9 |
Correct |
47 ms |
45768 KB |
Output is correct |
10 |
Correct |
46 ms |
45772 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
55 ms |
45820 KB |
Output is correct |
2 |
Correct |
49 ms |
45744 KB |
Output is correct |
3 |
Correct |
49 ms |
45820 KB |
Output is correct |
4 |
Correct |
50 ms |
45720 KB |
Output is correct |
5 |
Correct |
49 ms |
45772 KB |
Output is correct |
6 |
Correct |
47 ms |
45832 KB |
Output is correct |
7 |
Correct |
58 ms |
45768 KB |
Output is correct |
8 |
Correct |
47 ms |
45792 KB |
Output is correct |
9 |
Correct |
47 ms |
45768 KB |
Output is correct |
10 |
Correct |
46 ms |
45772 KB |
Output is correct |
11 |
Correct |
48 ms |
46032 KB |
Output is correct |
12 |
Correct |
48 ms |
45952 KB |
Output is correct |
13 |
Correct |
47 ms |
45772 KB |
Output is correct |
14 |
Correct |
54 ms |
45868 KB |
Output is correct |
15 |
Correct |
48 ms |
46208 KB |
Output is correct |
16 |
Correct |
47 ms |
45840 KB |
Output is correct |
17 |
Correct |
46 ms |
45900 KB |
Output is correct |
18 |
Correct |
47 ms |
45960 KB |
Output is correct |
19 |
Correct |
53 ms |
45848 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
55 ms |
45820 KB |
Output is correct |
2 |
Correct |
49 ms |
45744 KB |
Output is correct |
3 |
Correct |
49 ms |
45820 KB |
Output is correct |
4 |
Correct |
50 ms |
45720 KB |
Output is correct |
5 |
Correct |
49 ms |
45772 KB |
Output is correct |
6 |
Correct |
47 ms |
45832 KB |
Output is correct |
7 |
Correct |
58 ms |
45768 KB |
Output is correct |
8 |
Correct |
47 ms |
45792 KB |
Output is correct |
9 |
Correct |
47 ms |
45768 KB |
Output is correct |
10 |
Correct |
46 ms |
45772 KB |
Output is correct |
11 |
Correct |
48 ms |
46032 KB |
Output is correct |
12 |
Correct |
48 ms |
45952 KB |
Output is correct |
13 |
Correct |
47 ms |
45772 KB |
Output is correct |
14 |
Correct |
54 ms |
45868 KB |
Output is correct |
15 |
Correct |
48 ms |
46208 KB |
Output is correct |
16 |
Correct |
47 ms |
45840 KB |
Output is correct |
17 |
Correct |
46 ms |
45900 KB |
Output is correct |
18 |
Correct |
47 ms |
45960 KB |
Output is correct |
19 |
Correct |
53 ms |
45848 KB |
Output is correct |
20 |
Correct |
47 ms |
45992 KB |
Output is correct |
21 |
Correct |
46 ms |
46084 KB |
Output is correct |
22 |
Correct |
49 ms |
46864 KB |
Output is correct |
23 |
Correct |
48 ms |
45904 KB |
Output is correct |
24 |
Correct |
47 ms |
46432 KB |
Output is correct |
25 |
Correct |
51 ms |
46808 KB |
Output is correct |
26 |
Correct |
48 ms |
45784 KB |
Output is correct |
27 |
Correct |
47 ms |
47064 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
55 ms |
45820 KB |
Output is correct |
2 |
Correct |
49 ms |
45744 KB |
Output is correct |
3 |
Correct |
49 ms |
45820 KB |
Output is correct |
4 |
Correct |
50 ms |
45720 KB |
Output is correct |
5 |
Correct |
49 ms |
45772 KB |
Output is correct |
6 |
Correct |
47 ms |
45832 KB |
Output is correct |
7 |
Correct |
58 ms |
45768 KB |
Output is correct |
8 |
Correct |
47 ms |
45792 KB |
Output is correct |
9 |
Correct |
47 ms |
45768 KB |
Output is correct |
10 |
Correct |
46 ms |
45772 KB |
Output is correct |
11 |
Correct |
48 ms |
46032 KB |
Output is correct |
12 |
Correct |
48 ms |
45952 KB |
Output is correct |
13 |
Correct |
47 ms |
45772 KB |
Output is correct |
14 |
Correct |
54 ms |
45868 KB |
Output is correct |
15 |
Correct |
48 ms |
46208 KB |
Output is correct |
16 |
Correct |
47 ms |
45840 KB |
Output is correct |
17 |
Correct |
46 ms |
45900 KB |
Output is correct |
18 |
Correct |
47 ms |
45960 KB |
Output is correct |
19 |
Correct |
53 ms |
45848 KB |
Output is correct |
20 |
Correct |
47 ms |
45992 KB |
Output is correct |
21 |
Correct |
46 ms |
46084 KB |
Output is correct |
22 |
Correct |
49 ms |
46864 KB |
Output is correct |
23 |
Correct |
48 ms |
45904 KB |
Output is correct |
24 |
Correct |
47 ms |
46432 KB |
Output is correct |
25 |
Correct |
51 ms |
46808 KB |
Output is correct |
26 |
Correct |
48 ms |
45784 KB |
Output is correct |
27 |
Correct |
47 ms |
47064 KB |
Output is correct |
28 |
Correct |
48 ms |
46000 KB |
Output is correct |
29 |
Correct |
50 ms |
47332 KB |
Output is correct |
30 |
Correct |
53 ms |
48500 KB |
Output is correct |
31 |
Correct |
51 ms |
45864 KB |
Output is correct |
32 |
Correct |
54 ms |
47436 KB |
Output is correct |
33 |
Correct |
52 ms |
48800 KB |
Output is correct |
34 |
Correct |
56 ms |
50160 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
55 ms |
45820 KB |
Output is correct |
2 |
Correct |
49 ms |
45744 KB |
Output is correct |
3 |
Correct |
49 ms |
45820 KB |
Output is correct |
4 |
Correct |
50 ms |
45720 KB |
Output is correct |
5 |
Correct |
49 ms |
45772 KB |
Output is correct |
6 |
Correct |
47 ms |
45832 KB |
Output is correct |
7 |
Correct |
58 ms |
45768 KB |
Output is correct |
8 |
Correct |
47 ms |
45792 KB |
Output is correct |
9 |
Correct |
47 ms |
45768 KB |
Output is correct |
10 |
Correct |
46 ms |
45772 KB |
Output is correct |
11 |
Correct |
48 ms |
46032 KB |
Output is correct |
12 |
Correct |
48 ms |
45952 KB |
Output is correct |
13 |
Correct |
47 ms |
45772 KB |
Output is correct |
14 |
Correct |
54 ms |
45868 KB |
Output is correct |
15 |
Correct |
48 ms |
46208 KB |
Output is correct |
16 |
Correct |
47 ms |
45840 KB |
Output is correct |
17 |
Correct |
46 ms |
45900 KB |
Output is correct |
18 |
Correct |
47 ms |
45960 KB |
Output is correct |
19 |
Correct |
53 ms |
45848 KB |
Output is correct |
20 |
Correct |
47 ms |
45992 KB |
Output is correct |
21 |
Correct |
46 ms |
46084 KB |
Output is correct |
22 |
Correct |
49 ms |
46864 KB |
Output is correct |
23 |
Correct |
48 ms |
45904 KB |
Output is correct |
24 |
Correct |
47 ms |
46432 KB |
Output is correct |
25 |
Correct |
51 ms |
46808 KB |
Output is correct |
26 |
Correct |
48 ms |
45784 KB |
Output is correct |
27 |
Correct |
47 ms |
47064 KB |
Output is correct |
28 |
Correct |
48 ms |
46000 KB |
Output is correct |
29 |
Correct |
50 ms |
47332 KB |
Output is correct |
30 |
Correct |
53 ms |
48500 KB |
Output is correct |
31 |
Correct |
51 ms |
45864 KB |
Output is correct |
32 |
Correct |
54 ms |
47436 KB |
Output is correct |
33 |
Correct |
52 ms |
48800 KB |
Output is correct |
34 |
Correct |
56 ms |
50160 KB |
Output is correct |
35 |
Correct |
58 ms |
45900 KB |
Output is correct |
36 |
Correct |
83 ms |
55628 KB |
Output is correct |
37 |
Correct |
63 ms |
45836 KB |
Output is correct |
38 |
Correct |
74 ms |
50568 KB |
Output is correct |
39 |
Correct |
75 ms |
54200 KB |
Output is correct |
40 |
Correct |
95 ms |
57740 KB |
Output is correct |