#include <bits/stdc++.h>
#define pb push_back
#define ppb pop_back
#define fi first
#define se second
#define mid ((x + y) / 2)
#define left (ind * 2)
#define right (ind * 2 + 1)
#define mp make_pair
#define timer ((double)clock() / CLOCKS_PER_SEC)
#define endl "\n"
#define spc " "
#define d1(x) cerr<<#x<<":"<<x<<endl
#define d2(x, y) cerr<<#x<<":"<<x<<" "<<#y<<":"<<y<<endl
#define d3(x, y, z) cerr<<#x<<":"<<x<<" "<<#y<<":"<<y<<" "<<#z<<":"<<z<<endl
#define fast_io() ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
using namespace std;
typedef long long int lli;
typedef pair<int, int> ii;
typedef pair<ii, int> iii;
typedef pair<double, double> dd;
const int N = (int)(3e3 + 5);
const int LOG = (int)(20);
const int mod = (int)(1e9 + 7);
lli n, m, dp[N][N];
lli f(lli x, lli y)
{
lli re = 0;
if(x < 0 || y < 0)
return 0;
if(x == 0 || y == 0)
return 1;
if(dp[x][y] != -1)
return dp[x][y];
re += f(x - 1, y);
re += f(x - 1, y - 2) * y * (y - 1) / 2;
re += f(x - 2, y - 1) * (x - 1) * y;
re += f(x - 1, y - 1) * 4 * y;
return dp[x][y] = re % mod;
}
int main()
{
fast_io();
// freopen("inp.in", "r", stdin);
cin >> n >> m;
memset(dp, -1, sizeof dp);
cout << f(n, m) - 1;
}
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
59 ms |
71164 KB |
Output is correct |
| 2 |
Correct |
59 ms |
71164 KB |
Output is correct |
| 3 |
Correct |
60 ms |
71164 KB |
Output is correct |
| 4 |
Correct |
58 ms |
71280 KB |
Output is correct |
| 5 |
Correct |
60 ms |
71280 KB |
Output is correct |
| 6 |
Correct |
63 ms |
71280 KB |
Output is correct |
| 7 |
Correct |
60 ms |
71280 KB |
Output is correct |
| 8 |
Correct |
60 ms |
71280 KB |
Output is correct |
| 9 |
Correct |
62 ms |
71324 KB |
Output is correct |
| 10 |
Correct |
75 ms |
71324 KB |
Output is correct |
| 11 |
Correct |
60 ms |
71324 KB |
Output is correct |
| 12 |
Correct |
61 ms |
71324 KB |
Output is correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
59 ms |
71164 KB |
Output is correct |
| 2 |
Correct |
59 ms |
71164 KB |
Output is correct |
| 3 |
Correct |
60 ms |
71164 KB |
Output is correct |
| 4 |
Correct |
58 ms |
71280 KB |
Output is correct |
| 5 |
Correct |
60 ms |
71280 KB |
Output is correct |
| 6 |
Correct |
63 ms |
71280 KB |
Output is correct |
| 7 |
Correct |
60 ms |
71280 KB |
Output is correct |
| 8 |
Correct |
60 ms |
71280 KB |
Output is correct |
| 9 |
Correct |
62 ms |
71324 KB |
Output is correct |
| 10 |
Correct |
75 ms |
71324 KB |
Output is correct |
| 11 |
Correct |
60 ms |
71324 KB |
Output is correct |
| 12 |
Correct |
61 ms |
71324 KB |
Output is correct |
| 13 |
Correct |
61 ms |
71324 KB |
Output is correct |
| 14 |
Correct |
58 ms |
71324 KB |
Output is correct |
| 15 |
Correct |
282 ms |
71396 KB |
Output is correct |
| 16 |
Correct |
62 ms |
71396 KB |
Output is correct |
| 17 |
Correct |
94 ms |
71396 KB |
Output is correct |
| 18 |
Correct |
94 ms |
71396 KB |
Output is correct |
| 19 |
Correct |
235 ms |
71420 KB |
Output is correct |
| 20 |
Correct |
178 ms |
71420 KB |
Output is correct |
| 21 |
Correct |
133 ms |
71420 KB |
Output is correct |
| 22 |
Correct |
145 ms |
71420 KB |
Output is correct |
| 23 |
Correct |
111 ms |
71420 KB |
Output is correct |
| 24 |
Correct |
297 ms |
71456 KB |
Output is correct |
| 25 |
Correct |
228 ms |
71496 KB |
Output is correct |
| 26 |
Correct |
250 ms |
71496 KB |
Output is correct |
| 27 |
Correct |
282 ms |
71496 KB |
Output is correct |
