Submission #1115511

#	Time	Username	Problem	Language	Result	Execution time	Memory
1115511		Neco_arc	Tents (JOI18_tents)	C++17	0 / 100	2 ms	8528 KiB

tents

#include <bits/stdc++.h>

#define ll long long
#define ull unsigned long long
#define all(x) x.begin(), x.end()
#define Neco "flagger"
#define resp(x) sort(all(x)), x.resize(unique(all(x)) - x.begin())
#define getbit(x,i) ((x) >> (i))&1)
#define _left id * 2, l, mid
#define _right id * 2 + 1, mid + 1, r
#define cntbit(x) __builtin_popcountll(x)
#define fi(i, a, b) for(int i = a; i <= b; i++)
#define fid(i, a, b) for(int i = a; i >= b; i--)
#define maxn (int) (5e3 + 5)

using namespace std;

const ll mod = 1e9 + 7; //972663749

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll GetRandom(ll l, ll r) {
    return uniform_int_distribution<ll> (l, r)(rng);
}

int n, m;
ll f[maxn][maxn];

inline void Add(ll &x, ll y) {
    if((x += y) >= mod) x -= mod;
}

ll C(ll x) { return (x * (x - 1) / 2) % mod; }

void solve()
{

    cin >> n >> m;

    fi(i, 0, n) fi(j, 0, m) {
        if(i == 0 || j == 0) { f[i][j] = 1; continue; };

        ll val = (f[i - 1][j] + 4 * j % mod * f[i - 1][j - 1] % mod) % mod;
        Add(f[i][j], val);

        /// chon cung hang
        if(j >= 2) {
            ll val = C(j) * f[i - 1][j - 2];
            Add(f[i][j], val);
        }

        /// chon cung cot
        if(i >= 2) {
            ll val = (i - 1) * j % mod * f[i - 2][j - 1];
            Add(f[i][j], val);
        }
    }

    cout << (f[n][m] + mod - 1) % mod;

}

int main()
{

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    if(fopen(Neco".inp", "r")) {
        freopen(Neco".inp", "r", stdin);
        freopen(Neco".out", "w", stdout);
    }

    int nTest = 1;
//    cin >> nTest;

    while(nTest--)
    {
        solve();
    }


    return 0;
}

Compilation message (stderr)

tents.cpp: In function 'int main()':
tents.cpp:70:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |         freopen(Neco".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
tents.cpp:71:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |         freopen(Neco".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 48
• Subtask 2: 0 / 52