#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pi pair<int, int>
#define pii pair<int, pi>
#define fi first
#define se second
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
int memo[3005][3005];
const int mod = 1e9 + 7;
int dp(int x, int y){
if(x <= 0 || y <= 0)return 1;
if(memo[x][y] != -1)return memo[x][y];
return memo[x][y] = (y * (y - 1) / 2 % mod * dp(x - 1, y - 2) % mod + (x - 1) * y % mod * dp(x - 2, y - 1) % mod + 4 * y * dp(x - 1, y - 1) % mod + dp(x - 1, y) % mod)% mod;
}
void solve(){
int n, m; cin >> n >> m;
memset(memo, -1, sizeof(memo));
cout << (dp(n, m) - 1 + mod) % mod << '\n';
}
main(){
ios::sync_with_stdio(0);cin.tie(0);
int tc = 1;
//cin >> tc;
for(int tc1=1;tc1<=tc;tc1++){
// cout << "Case #" << tc1 << ": ";
solve();
}
}
Compilation message
tents.cpp:29:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
29 | main(){
| ^~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
71004 KB |
Output is correct |
2 |
Correct |
12 ms |
70928 KB |
Output is correct |
3 |
Correct |
13 ms |
70904 KB |
Output is correct |
4 |
Correct |
13 ms |
71136 KB |
Output is correct |
5 |
Correct |
13 ms |
70920 KB |
Output is correct |
6 |
Correct |
12 ms |
71136 KB |
Output is correct |
7 |
Correct |
14 ms |
71000 KB |
Output is correct |
8 |
Correct |
12 ms |
71112 KB |
Output is correct |
9 |
Correct |
13 ms |
71004 KB |
Output is correct |
10 |
Correct |
13 ms |
70928 KB |
Output is correct |
11 |
Correct |
12 ms |
71004 KB |
Output is correct |
12 |
Correct |
15 ms |
71000 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
13 ms |
71004 KB |
Output is correct |
2 |
Correct |
12 ms |
70928 KB |
Output is correct |
3 |
Correct |
13 ms |
70904 KB |
Output is correct |
4 |
Correct |
13 ms |
71136 KB |
Output is correct |
5 |
Correct |
13 ms |
70920 KB |
Output is correct |
6 |
Correct |
12 ms |
71136 KB |
Output is correct |
7 |
Correct |
14 ms |
71000 KB |
Output is correct |
8 |
Correct |
12 ms |
71112 KB |
Output is correct |
9 |
Correct |
13 ms |
71004 KB |
Output is correct |
10 |
Correct |
13 ms |
70928 KB |
Output is correct |
11 |
Correct |
12 ms |
71004 KB |
Output is correct |
12 |
Correct |
15 ms |
71000 KB |
Output is correct |
13 |
Correct |
13 ms |
71000 KB |
Output is correct |
14 |
Correct |
13 ms |
71260 KB |
Output is correct |
15 |
Correct |
120 ms |
71260 KB |
Output is correct |
16 |
Correct |
15 ms |
71000 KB |
Output is correct |
17 |
Correct |
24 ms |
71004 KB |
Output is correct |
18 |
Correct |
40 ms |
71000 KB |
Output is correct |
19 |
Correct |
163 ms |
71260 KB |
Output is correct |
20 |
Correct |
114 ms |
71260 KB |
Output is correct |
21 |
Correct |
72 ms |
71260 KB |
Output is correct |
22 |
Correct |
86 ms |
71456 KB |
Output is correct |
23 |
Correct |
57 ms |
71256 KB |
Output is correct |
24 |
Correct |
197 ms |
71356 KB |
Output is correct |
25 |
Correct |
137 ms |
71320 KB |
Output is correct |
26 |
Correct |
167 ms |
71568 KB |
Output is correct |
27 |
Correct |
176 ms |
71348 KB |
Output is correct |