#include<bits/stdc++.h>
#define int long long
#define pii pair<int, int>
using namespace std;
const int MOD=1e9+7;
signed main() {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n, m; cin >> n >> m;
vector<vector<int>> dp(n+1, vector<int>(m+1));
vector<vector<int>> pre(n+1, vector<int>(m+1));
dp[0][0]=pre[0][0]=1;
for(int i=1; i<=n; i++) dp[i][0]=pre[i][0]=1;
for(int j=1; j<=m; j++) dp[0][j]=pre[0][j]=1;
for(int i=1; i<=n; i++) {
for(int j=1; j<=m; j++) {
for(int k=1; k<=m; k++) pre[i][j]+=dp[i][k];
for(int k=1; k<=n; k++) pre[i][j]+=dp[k][j];
if(i>=2) dp[i][j]=(dp[i][j]+i*(i-1)/2*dp[i-2][j-1]+pre[i-2][j-1])%MOD;
if(j>=2) dp[i][j]=(dp[i][j]+i*(j-1)*dp[i-1][j-2]+pre[i-1][j-2])%MOD;
dp[i][j]=(dp[i][j]+dp[i][j-1])%MOD;
dp[i][j]=(dp[i][j]+4LL*i*dp[i-1][j-1]%MOD)%MOD;
if(i>=2) dp[i][j]=(dp[i][j]-pre[i-2][j-1]+MOD)%MOD;
if(j>=2) dp[i][j]=(dp[i][j]-pre[i-1][j-2]+MOD)%MOD;
pre[i][j]=(dp[i][j]+pre[i-1][j]+pre[i][j-1]-pre[i-1][j-1]+MOD)%MOD;
}
}
cout << dp[n][m]-1 << '\n';
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
340 KB |
Output is correct |
5 |
Correct |
3 ms |
468 KB |
Output is correct |
6 |
Correct |
4 ms |
596 KB |
Output is correct |
7 |
Correct |
4 ms |
596 KB |
Output is correct |
8 |
Correct |
3 ms |
468 KB |
Output is correct |
9 |
Correct |
0 ms |
212 KB |
Output is correct |
10 |
Correct |
12 ms |
852 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
38 ms |
1748 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
340 KB |
Output is correct |
5 |
Correct |
3 ms |
468 KB |
Output is correct |
6 |
Correct |
4 ms |
596 KB |
Output is correct |
7 |
Correct |
4 ms |
596 KB |
Output is correct |
8 |
Correct |
3 ms |
468 KB |
Output is correct |
9 |
Correct |
0 ms |
212 KB |
Output is correct |
10 |
Correct |
12 ms |
852 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
38 ms |
1748 KB |
Output is correct |
13 |
Correct |
2 ms |
340 KB |
Output is correct |
14 |
Correct |
7 ms |
468 KB |
Output is correct |
15 |
Execution timed out |
2081 ms |
88048 KB |
Time limit exceeded |
16 |
Halted |
0 ms |
0 KB |
- |