//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
#define ll long long
#define ii pair<int, int>
#define vi vector<int>
#define vll vector<ll>
#define vii vector<ii>
#define cd complex<double>
#define ld long double
#define all(x) (x).begin(), (x).end()
#define iii tuple<int, int, int>
const ll mod = 1e9 + 7;
const ll INF = 1e18L + 5;
const double PI = acos(-1);
const int block = 320;
const int N = 1e7;
int tc, tt = 1;
ll h, w;
ll fac[N + 5], inv[N + 5];
ll g[N + 5];
ll f[N + 5];
ll powmod(ll a, ll b) {
ll ans = 1;
while(b) {
if(b & 1) ans = ans * a % mod;
a = a * a % mod;
b /= 2;
}
return ans;
}
void prep() {
fac[0] = 1;
for(int i=1; i<=N; i++) fac[i] = fac[i - 1] * i % mod;
inv[N] = powmod(fac[N], mod - 2);
for(ll i=N-1; i>=0; i--)
inv[i] = inv[i + 1] * (i + 1) % mod;
}
ll C(ll n, ll k) {
ll ans = fac[n];
ans = ans * inv[k] % mod;
ans = ans * inv[n - k] % mod;
return ans;
}
void solve() {
prep();
f[0] = 1;
for(int i=1; i<=N; i++) f[i] = f[i - 1] * 4 % mod;
g[0] = 1;
for(int i=2; i<=N; i+=2) g[i] = g[i - 2] * C(i, 2) % mod;
cin>>h>>w;
ll ans = 0;
for(int i=0; i<=min(h, w/2); i++) {
ll cal = C(h, i) * C(w, i * 2) % mod;
cal = cal * g[i * 2] % mod;
for(int j=0; j<=min(w - 2 * i, (h - i)/2); j++) {
ll cal2 = C(w - 2 * i, j) * C(h - i, j * 2) % mod;
cal2 = cal2 * g[j * 2] % mod;
ll cnt = min((w - 2 * i - j), (h - i - j * 2));
ll fical = cal * cal2 % mod;
ll sum = 0;
for(int k=0; k<=cnt; k++) {
if(i == 0 && j == 0 && k == 0) continue;
ll v = f[k];
v = v * C(w - 2*i - j, k) % mod;
v = v * C(h - i - j * 2, k) % mod;
v = v * fac[k] % mod;
sum = (sum + v) % mod;
}
fical = fical * sum % mod;
ans = (ans + fical) % mod;
}
}
cout<<ans;
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
for(tc=1; tc<=tt; tc++) solve();
cerr<<"\nTime elapsed: "<<1000.0*clock()/CLOCKS_PER_SEC<<" ms.\n";
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
270 ms |
313428 KB |
Output is correct |
2 |
Correct |
279 ms |
313424 KB |
Output is correct |
3 |
Correct |
255 ms |
313428 KB |
Output is correct |
4 |
Correct |
255 ms |
313428 KB |
Output is correct |
5 |
Correct |
255 ms |
313360 KB |
Output is correct |
6 |
Correct |
255 ms |
313428 KB |
Output is correct |
7 |
Correct |
255 ms |
313424 KB |
Output is correct |
8 |
Correct |
257 ms |
313348 KB |
Output is correct |
9 |
Correct |
280 ms |
313520 KB |
Output is correct |
10 |
Correct |
259 ms |
313504 KB |
Output is correct |
11 |
Correct |
253 ms |
313320 KB |
Output is correct |
12 |
Correct |
287 ms |
313424 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
270 ms |
313428 KB |
Output is correct |
2 |
Correct |
279 ms |
313424 KB |
Output is correct |
3 |
Correct |
255 ms |
313428 KB |
Output is correct |
4 |
Correct |
255 ms |
313428 KB |
Output is correct |
5 |
Correct |
255 ms |
313360 KB |
Output is correct |
6 |
Correct |
255 ms |
313428 KB |
Output is correct |
7 |
Correct |
255 ms |
313424 KB |
Output is correct |
8 |
Correct |
257 ms |
313348 KB |
Output is correct |
9 |
Correct |
280 ms |
313520 KB |
Output is correct |
10 |
Correct |
259 ms |
313504 KB |
Output is correct |
11 |
Correct |
253 ms |
313320 KB |
Output is correct |
12 |
Correct |
287 ms |
313424 KB |
Output is correct |
13 |
Correct |
257 ms |
313512 KB |
Output is correct |
14 |
Correct |
266 ms |
313424 KB |
Output is correct |
15 |
Execution timed out |
2090 ms |
313700 KB |
Time limit exceeded |
16 |
Halted |
0 ms |
0 KB |
- |