Submission #370844

#	Time	Username	Problem	Language	Result	Execution time	Memory
370844		farhan132	Tents (JOI18_tents)	C++17	100 / 100	466 ms	71404 KiB

tents

/***Farhan132***/

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
typedef double dd;
typedef vector<ll> vll;
typedef pair<ll , ll> ii;
typedef vector< ii > vii;
typedef pair < ll , pair < ll , ll > > cm; 
 
#define ff first
#define ss second
#define pb push_back
#define in insert
#define f0(b) for(int i=0;i<(b);i++)
#define f00(b) for(int j=0;j<(b);j++)
#define f1(b) for(int i=1;i<=(b);i++)
#define f11(b) for(int j=1;j<=(b);j++)
#define f2(a,b) for(int i=(a);i<=(b);i++)
#define f22(a,b) for(int j=(a);j<=(b);j++)
#define sf(a) scanf("%lld",&a)
#define sff(a,b) scanf("%lld %lld", &a , &b)
#define pf(a) printf("%lld\n",a)
#define pff(a,b) printf("%lld %lld\n", a , b)
#define PI 3.14159265359
#define bug printf("**!\n")
#define mem(a , b) memset(a, b ,sizeof(a))
#define front_zero(n) __builtin_clzll(n)
#define back_zero(n) __builtin_ctzll(n)
#define total_one(n) __builtin_popcountll(n)
#define clean fflush(stdout)

const ll mod =  (ll)1e9 + 7;
const ll maxn = (ll)2e5 + 5;
const int nnn = 1048590;
const int inf = numeric_limits<int>::max()-1;
//const ll INF = numeric_limits<ll>::max()-1;
//const ll INF = 1e18;
 
ll dx[]={0,1,0,-1};
ll dy[]={1,0,-1,0};
ll dxx[]={0,1,0,-1,1,1,-1,-1};
ll dyy[]={1,0,-1,0,1,-1,1,-1};

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());

const ll N = 3005;

ll dp[N][N];

ll DP(ll x, ll y){

  if(min(x,y) == 0) return 1;
  ll &ret = dp[x][y];
  if(ret != -1) return ret;
  ret = ((y) * 4 * DP(x-1, y-1) )%mod;
  if(y >= 2) ret = (ret + ((y)*(y-1))/2 * DP(x-1, y-2))%mod;
  if(x >= 2 && y >= 1) ret = (ret + DP(x-2, y-1)*((x-1))*y )%mod;
  ret = ret + DP(x-1, y);
  return ret % mod;
}

void solve(){
  mem(dp, -1);
  ll n , m;
  cin >> n >> m;
  cout << (DP(n , m) + mod - 1) % mod;
  
  return;
}

 
int main() {
    
    
    #ifdef LOCAL
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
    #else 
     //   freopen("cbarn2.in", "r", stdin);
     //   freopen("cbarn2.out", "w", stdout);
      ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
    #endif
    //cout << fixed << setprecision(10);
   // work();
    //  mem(b,0);
    ll T;
    T=1;
    //cin >> T; 
    //scanf("%lld",&T);
   // ll CT = 0;
    //work();
    while(T--){
        //cout << "Case " << ++CT <<": " ;
        //printf("Case %lld: ",++CT);
        solve();
    }
 
    return 0;
}

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