Submission #966593

#	Time	Username	Problem	Language	Result	Execution time	Memory
966593		Tuanlinh123	Tents (JOI18_tents)	C++17	100 / 100	75 ms	70808 KiB

tents

#include<bits/stdc++.h>
#define ll long long
#define pll pair<ll, ll>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define ld long double
#define sz(a) ((ll)(a).size())
using namespace std;

const ll maxn=3005, Mod=1e9+7;
ll dp[maxn][maxn];
void upd(ll &a, ll b) {a+=b; if (a>=Mod) a-=Mod;}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    ll n, m; cin >> n >> m;
    for (ll i=0; i<=n; i++) dp[i][0]=1;
    for (ll i=0; i<=m; i++) dp[0][i]=1;
    for (ll i=1; i<=n; i++)
        for (ll j=1; j<=m; j++)
        {
            upd(dp[i][j], dp[i-1][j]);
            upd(dp[i][j], dp[i-1][j-1]*j*4%Mod);
            if (j>=2) upd(dp[i][j], dp[i-1][j-2]*(j*(j-1)/2)%Mod);
            if (i>=2) upd(dp[i][j], dp[i-2][j-1]*j*(i-1)%Mod);
        }
    cout << (dp[n][m]+Mod-1)%Mod;
}

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