#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int MOD = 1e9 + 7;
void norm(ll &x) {
if(x >= MOD) x -= MOD;
if(x < 0) x += MOD;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
int h, w;
cin >> h >> w;
vector<vector<ll>> dp(w + 10, vector<ll>(w + 10));
dp[0][0] = 1;
for(ll i = 1; i <= h; i++) {
vector<vector<ll>> new_dp(w + 10, vector<ll>(w + 10));
for(ll j = 0; j <= w; j++) {
for(ll k = 0; k <= j; k++) {
ll val = dp[j][k];
if(!val) continue;
new_dp[j][k] += val,
norm(new_dp[j][k]);
new_dp[j + 2][k] += (w - j) * (w - j - 1) / 2 * val % MOD,
norm(new_dp[j + 2][k]);
new_dp[j + 1][k] += (w - j) * 4 * val % MOD;
norm(new_dp[j + 1][k]);
new_dp[j + 1][k + 1] += val * (w - j) % MOD;
norm(new_dp[j + 1][k + 1]);
if(!k) continue;
new_dp[j][k - 1] += val * k % MOD;
norm(new_dp[j][k - 1]);
}
}
dp = new_dp;
}
ll ans = 0;
for(int j = 1; j <= w; j++) ans += dp[j][0], norm(ans);
cout << ans;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
852 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
12 ms |
1412 KB |
Output is correct |
6 |
Correct |
19 ms |
468 KB |
Output is correct |
7 |
Correct |
16 ms |
1180 KB |
Output is correct |
8 |
Correct |
12 ms |
388 KB |
Output is correct |
9 |
Correct |
0 ms |
212 KB |
Output is correct |
10 |
Correct |
60 ms |
668 KB |
Output is correct |
11 |
Correct |
3 ms |
1784 KB |
Output is correct |
12 |
Correct |
220 ms |
1844 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
852 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
12 ms |
1412 KB |
Output is correct |
6 |
Correct |
19 ms |
468 KB |
Output is correct |
7 |
Correct |
16 ms |
1180 KB |
Output is correct |
8 |
Correct |
12 ms |
388 KB |
Output is correct |
9 |
Correct |
0 ms |
212 KB |
Output is correct |
10 |
Correct |
60 ms |
668 KB |
Output is correct |
11 |
Correct |
3 ms |
1784 KB |
Output is correct |
12 |
Correct |
220 ms |
1844 KB |
Output is correct |
13 |
Correct |
27 ms |
54124 KB |
Output is correct |
14 |
Correct |
1 ms |
212 KB |
Output is correct |
15 |
Execution timed out |
2058 ms |
65324 KB |
Time limit exceeded |
16 |
Halted |
0 ms |
0 KB |
- |