Submission #1093152

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093152		vjudge1	Tents (JOI18_tents)	C++17	100 / 100	247 ms	82984 KiB

tents

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define int long long
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (b); i >= (a); i --)
#define REP(i, a) for (int i = 0; i < (a); ++i)
#define REPD(i, a) for (int i = (a) - 1; i >= 0; --i)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)


constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

/*
    Phu Trong from Nguyen Tat Thanh High School for gifted student
*/

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
#define MAX                 4444

int N, M;
int chooseTwo(int x){
    return x * (x - 1) / 2 % Mod;
}
void add(int &x, int y){
    x += y;
    if (x >= Mod) x %= Mod;
}
int mul(int a, int b){
    return 1LL * a * b % Mod;
}
int dp[MAX][MAX];
void process(void){
    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]);
            if(j >= 2) add(dp[i][j], mul(dp[i - 1][j - 2], chooseTwo(j)));
            if(i >= 2) add(dp[i][j], mul(mul(dp[i - 2][j - 1], i - 1), j));
            add(dp[i][j], dp[i - 1][j - 1] * j * 4 % Mod);
        }
    }
    cout << (dp[N][M] - 1 + Mod) % Mod;
}
signed main(){
    #define name "Whisper"
    cin.tie(nullptr) -> sync_with_stdio(false);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);
    process();
    return (0 ^ 0);
}

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