#include <iostream>
#include <cstdio>
#include <algorithm>
#include <string.h>
using namespace std;
#define endl '\n'
#define pi pair<int, int>
#define f first
#define s second
#define ll long long
const int mod = 1000000007;
const int maxn = 603;
int n;
bool a[2 * maxn];
int p[maxn], dp[maxn], dp2[maxn];
int c[maxn][maxn], f[maxn][maxn];
int main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
cin >> n;
for(int i = 0; i < n; i++){
int x;
cin >> x;
a[x] = 1;
}
f[0][0] = 1;
for(int i = 0; i < n; i++)
for(int j = i; j <= 2 * i && j < n; j++){
(f[i + 1][j + 2] += f[i][j]) %= mod;
(f[i + 1][j + 1] += 2 * f[i][j] % mod) %= mod;
(f[i + 1][j] += f[i][j]) %= mod;
}
c[0][0] = 1;
for(int i = 0, j = 1; i < n; i++){
p[i] = (ll)f[i][i] * j % mod * (i + 2) % mod;
j = (ll)j * (i + 1) % mod;
for(int k = 0; k <= i; k++){
(c[i + 1][k] += c[i][k]) %= mod;
(c[i + 1][k + 1] += c[i][k]) %= mod;
}
}
dp[0] = 1;
for(int i = 2 * n, x = 0, y = 0; i > 0 && y <= x; i--){
if(a[i]){
memcpy(dp2 + y, dp + y, (x - y + 1) * sizeof(int));
for(int j = y; j <= x; j++)
for(int k = j; k <= x; k++){
(dp[k + 1] += (ll)dp2[j] * c[x - j][k - j] % mod * p[k - j] % mod) %= mod;
}
x++;
}else{
for(int j = y; j <= x; j++) dp[j] = (ll)dp[j] * (j - y) % mod;
y++;
}
}
int ret = dp[n];
for(int i = n, j = (mod + 1) / 2; i; i >>= 1){
if(i & 1) ret = (ll)ret * j % mod;
j = (ll)j * j % mod;
}
cout << ret << endl;
return 0;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
4 ms |
384 KB |
Output is correct |
| 2 |
Correct |
4 ms |
384 KB |
Output is correct |
| 3 |
Correct |
4 ms |
384 KB |
Output is correct |
| 4 |
Correct |
5 ms |
384 KB |
Output is correct |
| 5 |
Correct |
5 ms |
384 KB |
Output is correct |
| 6 |
Correct |
5 ms |
384 KB |
Output is correct |
| 7 |
Correct |
4 ms |
384 KB |
Output is correct |
| 8 |
Correct |
5 ms |
384 KB |
Output is correct |
| 9 |
Correct |
5 ms |
384 KB |
Output is correct |
| 10 |
Correct |
5 ms |
384 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
4 ms |
384 KB |
Output is correct |
| 2 |
Correct |
4 ms |
384 KB |
Output is correct |
| 3 |
Correct |
4 ms |
384 KB |
Output is correct |
| 4 |
Correct |
5 ms |
384 KB |
Output is correct |
| 5 |
Correct |
5 ms |
384 KB |
Output is correct |
| 6 |
Correct |
5 ms |
384 KB |
Output is correct |
| 7 |
Correct |
4 ms |
384 KB |
Output is correct |
| 8 |
Correct |
5 ms |
384 KB |
Output is correct |
| 9 |
Correct |
5 ms |
384 KB |
Output is correct |
| 10 |
Correct |
5 ms |
384 KB |
Output is correct |
| 11 |
Correct |
5 ms |
640 KB |
Output is correct |
| 12 |
Correct |
5 ms |
640 KB |
Output is correct |
| 13 |
Correct |
5 ms |
640 KB |
Output is correct |
| 14 |
Correct |
5 ms |
640 KB |
Output is correct |
| 15 |
Correct |
8 ms |
640 KB |
Output is correct |
| 16 |
Correct |
5 ms |
640 KB |
Output is correct |
| 17 |
Correct |
5 ms |
640 KB |
Output is correct |
| 18 |
Correct |
5 ms |
640 KB |
Output is correct |
| 19 |
Correct |
5 ms |
640 KB |
Output is correct |
| 20 |
Correct |
5 ms |
640 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
4 ms |
384 KB |
Output is correct |
| 2 |
Correct |
4 ms |
384 KB |
Output is correct |
| 3 |
Correct |
4 ms |
384 KB |
Output is correct |
| 4 |
Correct |
5 ms |
384 KB |
Output is correct |
| 5 |
Correct |
5 ms |
384 KB |
Output is correct |
| 6 |
Correct |
5 ms |
384 KB |
Output is correct |
| 7 |
Correct |
4 ms |
384 KB |
Output is correct |
| 8 |
Correct |
5 ms |
384 KB |
Output is correct |
| 9 |
Correct |
5 ms |
384 KB |
Output is correct |
| 10 |
Correct |
5 ms |
384 KB |
Output is correct |
| 11 |
Correct |
5 ms |
640 KB |
Output is correct |
| 12 |
Correct |
5 ms |
640 KB |
Output is correct |
| 13 |
Correct |
5 ms |
640 KB |
Output is correct |
| 14 |
Correct |
5 ms |
640 KB |
Output is correct |
| 15 |
Correct |
8 ms |
640 KB |
Output is correct |
| 16 |
Correct |
5 ms |
640 KB |
Output is correct |
| 17 |
Correct |
5 ms |
640 KB |
Output is correct |
| 18 |
Correct |
5 ms |
640 KB |
Output is correct |
| 19 |
Correct |
5 ms |
640 KB |
Output is correct |
| 20 |
Correct |
5 ms |
640 KB |
Output is correct |
| 21 |
Correct |
9 ms |
3200 KB |
Output is correct |
| 22 |
Correct |
8 ms |
3200 KB |
Output is correct |
| 23 |
Correct |
9 ms |
3200 KB |
Output is correct |
| 24 |
Correct |
13 ms |
3200 KB |
Output is correct |
| 25 |
Correct |
8 ms |
3200 KB |
Output is correct |
| 26 |
Correct |
8 ms |
3200 KB |
Output is correct |
| 27 |
Correct |
8 ms |
3200 KB |
Output is correct |
| 28 |
Correct |
8 ms |
3200 KB |
Output is correct |
| 29 |
Correct |
8 ms |
3200 KB |
Output is correct |
| 30 |
Correct |
252 ms |
3200 KB |
Output is correct |
| 31 |
Correct |
139 ms |
3200 KB |
Output is correct |
| 32 |
Correct |
174 ms |
3200 KB |
Output is correct |
| 33 |
Correct |
215 ms |
3200 KB |
Output is correct |
| 34 |
Correct |
121 ms |
3200 KB |
Output is correct |
| 35 |
Correct |
186 ms |
3200 KB |
Output is correct |
| 36 |
Correct |
220 ms |
3200 KB |
Output is correct |
