#include <bits/stdc++.h>
typedef long long int ll;
typedef long double ld;
typedef unsigned long long int ull;
typedef long int li;
#define fastio ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define test ll t; cin >> t; while(t--)
const long long int dx[4] = {0, 0, -1, 1}, dy[4] = {1, -1, 0, 0};
const long long int cons = 3005, ncr_cons = 100005;
const long long int MOD = 1000000007; // const long long int MOD = 998244353;
const long long int const_INT_MAX = 1000000000000000000, const_INT_MIN = -1 * 1000000000000000000;
using namespace std;
bool sortinrev(const pair<ll,ll> &a, const pair<ll,ll> &b){return (a.first > b.first);}
bool sortbysec(const pair<ll,ll> &a, const pair<ll,ll> &b){return (a.second < b.second);}
bool sortbysecinrev(const pair<ll,ll> &a, const pair<ll,ll> &b){return (a.second > b.second);}
ll gcd(ll x, ll y){return (ll)(__gcd(x, y));}
ll lcm(ll x, ll y){return (ll)((x * y) / gcd(x, y));}
ll mod_expo(ll x, ll y, ll p){
ll res = 1;
if((x + p) % p == 0){
return res = 0;
}
x = (x + p) % p;
while (y > 0){
if(y & 1) res = (res*x + p) % p;
y = y>>1; x = (x*x + p) % p;
}
return res;
}
void usaco(string str = ""){
fastio;
if(str.size()){
freopen((str + ".in").c_str(), "r", stdin);
freopen((str + ".out").c_str(), "w", stdout);
}
}
ll invnum[ncr_cons], invfac[ncr_cons], fac[ncr_cons];
void pre_ncr(){ // add pre_ncr() in main
invnum[0] = invnum[1] = invfac[0] = invfac[1] = fac[0] = 1;
for(ll i=2;i<ncr_cons;i++){
invnum[i] = ((invnum[MOD % i] * (MOD - (MOD / i)) + MOD) % MOD);
}
for(ll i=2;i<ncr_cons;i++){
invfac[i] = ((invnum[i] * invfac[i-1] + MOD) % MOD);
}
for(ll i=1;i<ncr_cons;i++){
fac[i] = ((fac[i-1] * i + MOD) % MOD);
}
}
ll ncr(ll n, ll r){
ll ans = ((fac[n] * invfac[r] + MOD) % MOD) * ((invfac[n-r] + MOD) % MOD);
ans += MOD; ans %= MOD; return ans;
}
ll dp[cons][cons];
ll solve(ll h, ll w){
if(min(h, w) < 0) return 0;
if(dp[h][w] != -1) return dp[h][w];
ll var = 0;
var += (ll)(((solve(h-1, w-1) * h + MOD) % MOD * 4 + MOD) % MOD); var %= MOD;
var += (ll)(solve(h, w-1)); var %= MOD;
var += (ll)(((solve(h-2, w-1) + MOD) % MOD) * ((ncr(h, 2) + MOD) % MOD)); var %= MOD;
var += (ll)(((solve(h-1, w-2) + MOD) % MOD) * ((h * (w-1) + MOD) % MOD)); var %= MOD;
return dp[h][w] = var;
}
int main(){
usaco(); pre_ncr();
for(ll i=0;i<cons;i++){
for(ll j=0;j<cons;j++){
if(!(min(i, j))) dp[i][j] = 1;
else dp[i][j] = -1;
}
}
ll h, w; cin >> h >> w;
ll var = solve(h, w); var--; var += MOD; var %= MOD; cout << var << "\n";
cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
}
Compilation message
tents.cpp: In function 'void usaco(std::string)':
tents.cpp:34:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
34 | freopen((str + ".in").c_str(), "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tents.cpp:35:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
35 | freopen((str + ".out").c_str(), "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
52 ms |
73324 KB |
Output is correct |
2 |
Correct |
59 ms |
73324 KB |
Output is correct |
3 |
Correct |
50 ms |
73452 KB |
Output is correct |
4 |
Correct |
51 ms |
73356 KB |
Output is correct |
5 |
Correct |
51 ms |
73452 KB |
Output is correct |
6 |
Correct |
53 ms |
73324 KB |
Output is correct |
7 |
Correct |
52 ms |
73452 KB |
Output is correct |
8 |
Correct |
51 ms |
73324 KB |
Output is correct |
9 |
Correct |
51 ms |
73324 KB |
Output is correct |
10 |
Correct |
52 ms |
73324 KB |
Output is correct |
11 |
Correct |
52 ms |
73452 KB |
Output is correct |
12 |
Correct |
54 ms |
73452 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
52 ms |
73324 KB |
Output is correct |
2 |
Correct |
59 ms |
73324 KB |
Output is correct |
3 |
Correct |
50 ms |
73452 KB |
Output is correct |
4 |
Correct |
51 ms |
73356 KB |
Output is correct |
5 |
Correct |
51 ms |
73452 KB |
Output is correct |
6 |
Correct |
53 ms |
73324 KB |
Output is correct |
7 |
Correct |
52 ms |
73452 KB |
Output is correct |
8 |
Correct |
51 ms |
73324 KB |
Output is correct |
9 |
Correct |
51 ms |
73324 KB |
Output is correct |
10 |
Correct |
52 ms |
73324 KB |
Output is correct |
11 |
Correct |
52 ms |
73452 KB |
Output is correct |
12 |
Correct |
54 ms |
73452 KB |
Output is correct |
13 |
Correct |
51 ms |
73580 KB |
Output is correct |
14 |
Correct |
52 ms |
73452 KB |
Output is correct |
15 |
Correct |
295 ms |
73732 KB |
Output is correct |
16 |
Correct |
70 ms |
73452 KB |
Output is correct |
17 |
Correct |
104 ms |
73580 KB |
Output is correct |
18 |
Correct |
114 ms |
73580 KB |
Output is correct |
19 |
Correct |
342 ms |
73708 KB |
Output is correct |
20 |
Correct |
277 ms |
73708 KB |
Output is correct |
21 |
Correct |
200 ms |
73580 KB |
Output is correct |
22 |
Correct |
186 ms |
73556 KB |
Output is correct |
23 |
Correct |
72 ms |
73472 KB |
Output is correct |
24 |
Correct |
467 ms |
73708 KB |
Output is correct |
25 |
Correct |
355 ms |
73580 KB |
Output is correct |
26 |
Correct |
404 ms |
73708 KB |
Output is correct |
27 |
Correct |
469 ms |
73708 KB |
Output is correct |