Submission #144535

#	Time	Username	Problem	Language	Result	Execution time	Memory
144535		cheetose	Tents (JOI18_tents)	C++11	100 / 100	427 ms	71180 KiB

tents

#include<cstdio>
#include<cstdlib>
#include<iostream>
#include<vector>
#include<queue>
#include<bitset>
#include<string>
#include<stack>
#include<set>
#include<unordered_set>
#include<map>
#include<unordered_map>
#include<cstring>
#include<complex>
#include<cmath>
#include<iomanip>
#include<numeric>
#include<algorithm>
#include<list>
#include<functional>
#include<cassert>
#define mp make_pair
#define pb push_back
#define X first
#define Y second
#define y0 y12
#define y1 y22
#define INF 987654321
#define PI 3.141592653589793238462643383279502884
#define fup(i,a,b,c) for(int (i)=(a);(i)<=(b);(i)+=(c))
#define fdn(i,a,b,c) for(int (i)=(a);(i)>=(b);(i)-=(c))
#define MEM0(a) memset((a),0,sizeof(a));
#define MEM_1(a) memset((a),-1,sizeof(a));
#define ALL(a) a.begin(),a.end()
#define SYNC ios_base::sync_with_stdio(false);cin.tie(0)
using namespace std;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> Pi;
typedef pair<ll, ll> Pll;
typedef pair<ld, ld> Pd;
typedef vector<int> Vi;
typedef vector<ll> Vll;
typedef vector<double> Vd;
typedef vector<Pi> VPi;
typedef vector<Pll> VPll;
typedef vector<Pd> VPd;
typedef tuple<int, int, int> iii;
typedef tuple<int,int,int,int> iiii;
typedef tuple<ll, ll, ll> LLL;
typedef vector<iii> Viii;
typedef vector<LLL> VLLL;
typedef complex<double> base;
const ll MOD = 1000000007;
ll POW(ll a, ll b, ll MMM = MOD) {ll ret=1; for(;b;b>>=1,a=(a*a)%MMM)if(b&1)ret=(ret*a)% MMM; return ret; }
ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
ll lcm(ll a, ll b) { if (a == 0 || b == 0)return a + b; return a*(b / gcd(a, b)); }
int dx[] = { 0,1,0,-1,1,1,-1,-1 }, dy[] = { 1,0,-1,0,1,-1,1,-1 };

ll d[3001][3001];
inline void add(ll &a,ll b){a=(a+b)%MOD;}
inline ll nC2(int x){return 1LL*x*(x-1)/2;}
ll go(int N,int M)
{
	if(N*M==0)return 1;
	ll &ret=d[N][M];
	if(ret!=-1)return ret;
	ret=0;
	add(ret,go(N,M-1));
	add(ret,go(N-1,M-1)*4*N);
	if(N>=2)add(ret,nC2(N)*go(N-2,M-1));
	if(M>=2)add(ret,go(N-1,M-2)*N*(M-1));
	return ret;
}
int main() {
	MEM_1(d);
	int n,m;
	scanf("%d%d",&n,&m);
	ll ans=go(n,m)-1;
	add(ans,MOD);
	printf("%lld",ans);
}

Compilation message (stderr)

tents.cpp: In function 'int main()':
tents.cpp:81:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&m);
  ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 48 / 48
• Subtask 2: 52 / 52