#pragma GCC optimize("Ofast")
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <cwchar>
#include <cwctype>
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <array>
#include <atomic>
#include <chrono>
#include <codecvt>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
using namespace std;
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
const int MAXN = 2e5 + 10;
const int MOD = 1e9 + 7;
#define int long long
int rnd(int x, int y) {
int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
int f[MAXN];
int bm(int b, int p) {
if(p==0) return 1 % MOD;
int r = bm(b, p >> 1);
if(p & 1) return (((r * r) % MOD) * b) % MOD;
return (r * r) % MOD;
}
int inv(int b) {
return bm(b, MOD - 2);
}
int op[6001];
int nCr(int n, int r) {
int ans = f[n] * op[r];
ans %= MOD;
return (ans * op[n-r]) % MOD;
}
void solve(int tc) {
f[0] = 1;
for(int i=1; i<MAXN; i++) f[i] = (f[i-1] * i) % MOD;
for(int i=0; i<6001; i++) op[i] = inv(f[i]);
int H, W, ans = 0;
cin >> H >> W;
int cnt[H+1][W+1];
for(int i=0; i<=W; i++) cnt[0][i] = 1;
for(int i=0; i<=H; i++) cnt[i][0] = 1;
cnt[1][1] = 5;
for(int i=2; i<=H; i++) cnt[i][1] = 4*i + 1;
for(int i=2; i<=W; i++) cnt[1][i] = 4*i + 1;
for(int i=2; i<=H; i++) {
for(int j=2; j<=W; j++) {
cnt[i][j] = (cnt[i-1][j-1] * 5 + cnt[i-1][j-2] * 4 * (j-1) + cnt[i-2][j-1] * 4 * (i-1)) % MOD;
cnt[i][j] += (i-1) * (j-1) * 16 * cnt[i-2][j-2];
cnt[i][j] %= MOD;
}
}
int ono[6001];
for(int i=0; i<=6000; i++) ono[i] = inv(bm(2, i));
for(int x=0; x<=H; x++) {
for(int y=0; x+2*y<=H && y+2*x<=W; y++) {
int combs = nCr(H, x) * nCr(W, 2*x);
combs %= MOD;
combs *= f[2*x];
combs %= MOD;
combs *= ono[x];
combs %= MOD;
combs *= nCr(W-2*x, y);
combs %= MOD;
combs *= nCr(H-x, 2*y);
combs %= MOD;
combs *= f[2*y];
combs %= MOD;
combs *= ono[y];
combs %= MOD;
ans += combs * cnt[H - x - 2*y][W - y - 2*x];
ans %= MOD;
}
}
cout << (ans + MOD - 1) % MOD << "\n";
}
int32_t main(){
ios::sync_with_stdio(0); cin.tie(0);
int t = 1; //cin >> t;
for(int i=1; i<=t; i++) solve(i);
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
1868 KB |
Output is correct |
2 |
Correct |
5 ms |
1868 KB |
Output is correct |
3 |
Correct |
5 ms |
1860 KB |
Output is correct |
4 |
Correct |
5 ms |
1964 KB |
Output is correct |
5 |
Correct |
5 ms |
1996 KB |
Output is correct |
6 |
Correct |
4 ms |
2028 KB |
Output is correct |
7 |
Correct |
6 ms |
2124 KB |
Output is correct |
8 |
Correct |
5 ms |
2064 KB |
Output is correct |
9 |
Correct |
6 ms |
1972 KB |
Output is correct |
10 |
Correct |
7 ms |
2252 KB |
Output is correct |
11 |
Correct |
6 ms |
1996 KB |
Output is correct |
12 |
Correct |
6 ms |
2636 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
1868 KB |
Output is correct |
2 |
Correct |
5 ms |
1868 KB |
Output is correct |
3 |
Correct |
5 ms |
1860 KB |
Output is correct |
4 |
Correct |
5 ms |
1964 KB |
Output is correct |
5 |
Correct |
5 ms |
1996 KB |
Output is correct |
6 |
Correct |
4 ms |
2028 KB |
Output is correct |
7 |
Correct |
6 ms |
2124 KB |
Output is correct |
8 |
Correct |
5 ms |
2064 KB |
Output is correct |
9 |
Correct |
6 ms |
1972 KB |
Output is correct |
10 |
Correct |
7 ms |
2252 KB |
Output is correct |
11 |
Correct |
6 ms |
1996 KB |
Output is correct |
12 |
Correct |
6 ms |
2636 KB |
Output is correct |
13 |
Correct |
5 ms |
1996 KB |
Output is correct |
14 |
Correct |
5 ms |
1996 KB |
Output is correct |
15 |
Correct |
78 ms |
45748 KB |
Output is correct |
16 |
Correct |
8 ms |
4684 KB |
Output is correct |
17 |
Correct |
25 ms |
11728 KB |
Output is correct |
18 |
Correct |
24 ms |
13980 KB |
Output is correct |
19 |
Correct |
96 ms |
52988 KB |
Output is correct |
20 |
Correct |
75 ms |
42744 KB |
Output is correct |
21 |
Correct |
45 ms |
28748 KB |
Output is correct |
22 |
Correct |
44 ms |
28332 KB |
Output is correct |
23 |
Correct |
30 ms |
16564 KB |
Output is correct |
24 |
Correct |
137 ms |
72388 KB |
Output is correct |
25 |
Correct |
95 ms |
54184 KB |
Output is correct |
26 |
Correct |
118 ms |
61912 KB |
Output is correct |
27 |
Correct |
145 ms |
69700 KB |
Output is correct |