Submission #391967

# Submission time Handle Problem Language Result Execution time Memory
391967 2021-04-20T08:58:11 Z PixelCat Tents (JOI18_tents) C++14
100 / 100
171 ms 71108 KB
/*                                                       
  /^--^\                                                 
  \____/                                                 
 /      \ _____  _ __  __ ____  _     ____   ____  _____ 
|        || ()_)| |\ \/ /| ===|| |__ / (__` / () \|_   _|
 \__  __/ |_|   |_|/_/\_\|____||____|\____)/__/\__\ |_|  
|^|^\ \^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|^|
| | |\ \| | | | | | | | | | | | | | | | | | | | | | | | |
#####/ /#################################################
| | |\/ | | | | | | | | | | | | | | | | | | | | | | | | |
|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|*/
//#pragma GCC optimize("O4,unroll-loops,no-stack-protector")
#include <bits/stdc++.h>
#define int ll //__int128
#define double long double
using namespace std;
using ll=long long;
using ull=unsigned long long;
using pii=pair<int,int>;

#define For(i,a,b)    for(int i=a;i<=b;i++)
#define Fors(i,a,b,s) for(int i=a;i<=b;i+=s)
#define Forr(i,a,b)   for(int i=a;i>=b;i--)
#define F first
#define S second
#define L(id) (id*2+1)
#define R(id) (id*2+2)
#define LO(x) (x&(-x))

#define eb emplace_back
#define all(x) x.begin(),x.end()
#define sz(x) ((int)x.size())
#define mkp make_pair

#define MOD (int)(1000000007)
#define INF (int)(1e12)
#define EPS (1e-7)

#ifdef NYAOWO
#define debug(...) do{\
	cerr << __LINE__ <<\
	" : ("#__VA_ARGS__ << ") = ";\
	_OUT(__VA_ARGS__);\
	cerr << flush;\
}while(0)
template<typename T> void _OUT(T x) { cerr << x << "\n"; }
template<typename T,typename...I>
void _OUT(T x,I ...tail) { cerr << x << ", "; _OUT(tail...); }
#else
#define debug(...)
#endif
inline void NYA(){ ios::sync_with_stdio(false); cin.tie(0); }
inline void USACO(const string &s){
	freopen((s+".in").c_str(),"r",stdin);
	freopen((s+".out").c_str(),"w",stdout);
}

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
//int gcd(int a,int b) { return b==0?a:gcd(b,a%b); }
inline int gcd(int a,int b) { return __gcd(a,b); }
inline int lcm(int a,int b) { return a/gcd(a,b)*b; }
__int128 fpow(__int128 b,__int128 p,const __int128 &mod){
	__int128 ans=1;
	while(p){
		if(p&1) ans=ans*b%mod;
		p/=2; b=b*b%mod;
	}
	return ans;
}
int fpow(int b,int p) { return fpow(b,p,MOD); }
template<typename T> inline void chmin(T &_a,const T &_b) { if(_b<_a) _a=_b; }
template<typename T> inline void chmax(T &_a,const T &_b) { if(_b>_a) _a=_b; }

int dp[3010][3010];
int fac[3010];
int inv[3010];
int C(int n,int m){
	return fac[n]*inv[m]%MOD*inv[n-m]%MOD;
}

int32_t main(){
	NYA();
	//nachoneko so cute >/////<
	fac[0]=inv[0]=1;
	For(i,1,3000){
		fac[i]=fac[i-1]*i%MOD;
		inv[i]=fpow(fac[i],MOD-2);
	}
	int n,m; cin>>n>>m;
	dp[0][0]=1;
	int ans=0;
	For(i,1,n) For(j,1,m){
		dp[i][j]=dp[i-1][j-1]*4*j;
		if(i>=2) dp[i][j]+=dp[i-2][j-1]*(i-1)*j;
		if(j>=2) dp[i][j]+=dp[i-1][j-2]*j*(j-1)/2;
		dp[i][j]%=MOD;
		ans=(ans+dp[i][j]*C(n,i)%MOD*C(m,j))%MOD;
		debug(i,j,dp[i][j]);
	}
	cout<<ans<<"\n";
	return 0;
}
# Verdict Execution time Memory Grader output
1 Correct 2 ms 332 KB Output is correct
2 Correct 2 ms 332 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 3 ms 1228 KB Output is correct
5 Correct 3 ms 716 KB Output is correct
6 Correct 3 ms 1356 KB Output is correct
7 Correct 3 ms 844 KB Output is correct
8 Correct 3 ms 1484 KB Output is correct
9 Correct 3 ms 880 KB Output is correct
10 Correct 3 ms 1784 KB Output is correct
11 Correct 2 ms 376 KB Output is correct
12 Correct 4 ms 2304 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 2 ms 332 KB Output is correct
2 Correct 2 ms 332 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 3 ms 1228 KB Output is correct
5 Correct 3 ms 716 KB Output is correct
6 Correct 3 ms 1356 KB Output is correct
7 Correct 3 ms 844 KB Output is correct
8 Correct 3 ms 1484 KB Output is correct
9 Correct 3 ms 880 KB Output is correct
10 Correct 3 ms 1784 KB Output is correct
11 Correct 2 ms 376 KB Output is correct
12 Correct 4 ms 2304 KB Output is correct
13 Correct 2 ms 332 KB Output is correct
14 Correct 6 ms 9676 KB Output is correct
15 Correct 101 ms 55200 KB Output is correct
16 Correct 9 ms 4044 KB Output is correct
17 Correct 27 ms 12844 KB Output is correct
18 Correct 30 ms 17012 KB Output is correct
19 Correct 123 ms 63040 KB Output is correct
20 Correct 93 ms 50924 KB Output is correct
21 Correct 62 ms 33752 KB Output is correct
22 Correct 62 ms 35416 KB Output is correct
23 Correct 39 ms 27076 KB Output is correct
24 Correct 153 ms 71108 KB Output is correct
25 Correct 117 ms 61324 KB Output is correct
26 Correct 135 ms 66688 KB Output is correct
27 Correct 171 ms 69144 KB Output is correct