Submission #1097557

#	Time	Username	Problem	Language	Result	Execution time	Memory
1097557		TrinhKhanhDung	Tents (JOI18_tents)	C++14	100 / 100	94 ms	47356 KiB

tents

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18
#define INF (ll)1e9
#define MOD (ll)(1e9 + 7)

using namespace std;

template<class T1, class T2>
    bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}

template<class T1, class T2>
    bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}

template<class T1, class T2>
    void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}

template<class T1, class T2>
    void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}

template<class T>
    void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}

const int MAX = 4e3 + 10;

int N, M;
int dp[MAX][MAX];

void solve(){
    cin >> N >> M;

    for(int i = 0; i <= N; i++) dp[i][0] = 1;
    for(int i = 0; i <= M; i++) dp[0][i] = 1;

    for(int i = 1; i <= N; i++){
        for(int j = 1; j <= M; j++){
            add(dp[i][j], dp[i - 1][j]);
            add(dp[i][j], 4LL * j * dp[i - 1][j - 1] % MOD);
            if(j >= 2) add(dp[i][j], 1LL * dp[i - 1][j - 2] * (1LL * j * (j - 1) / 2 % MOD) % MOD);
            if(i >= 2) add(dp[i][j], 1LL * dp[i - 2][j - 1] * (i - 1) % MOD * j % MOD);
        }
    }

    int ans = dp[N][M];
    sub(ans, 1);

    cout << ans << '\n';
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
//     freopen("CAU3.inp","r",stdin);
//     freopen("CAU3.out","w",stdout);

    int t = 1;
//    cin >> t;
    while(t--){
        solve();
    }

    return 0;
}

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