oj.uz

Submission #525226

# Submission time Handle Problem Language Result Execution time Memory
525226 2022-02-11T07:06:31 Z AA_Surely Tents (JOI18_tents) C++17
100 / 100
 100 ms 71244 KB 
#include <bits/stdc++.h>

#define FOR(i,x,n) 	for(int i=x; i<n; i++)
#define F0R(i,n) 	FOR(i,0,n)
#define ROF(i,x,n) 	for(int i=n-1; i>=x; i--)
#define R0F(i,n) 	ROF(i,0,n)

#define WTF 		cout << "WTF" << endl

#define IOS 		ios::sync_with_stdio(false); cin.tie(0)
#define F 			first
#define S	 		second
#define pb 			push_back

#define ALL(x) 		x.begin(), x.end()
#define RALL(x) 	x.rbegin(), x.rend()

using namespace std;
typedef long long 		LL;

typedef pair<int, int> 	PII;
typedef pair<LL, LL> 	PLL;

typedef vector<int> 	VI;
typedef vector<LL> 		VLL;
typedef vector<PII> 	VPII;
typedef vector<PLL> 	VPLL;

const int MAXN = 3000 + 7;
const int ALPHA = 27;
const int INF = 1e9 + 7;
const int MOD = 1e9 + 7;
const int LOG = 22;

int n, m;
LL fact[MAXN << 1], inv_fact[MAXN << 1];
LL dp[MAXN << 1], f[MAXN][MAXN];

inline LL pw(LL a, LL b) {
    LL res = 1;
    for(; b; b >>= 1, a = a * a % MOD) 
        if (b & 1) res = res * a % MOD;
    return res;
}

inline LL nCr(int nn, int rr) {
    if (nn < rr || rr < 0) return 0;
    return (fact[nn] * inv_fact[rr] % MOD) * inv_fact[nn - rr] % MOD;
}

void precalc() {
    fact[0] = 1;
    FOR(i, 1, (MAXN << 1)) fact[i] = fact[i - 1] * i % MOD;

    inv_fact[(MAXN << 1) - 1] = pw(fact[(MAXN << 1) - 1], MOD - 2);
    R0F(i, (MAXN << 1) - 1) inv_fact[i] = inv_fact[i + 1] * (i + 1) % MOD;
    //cout << pw(8, MOD - 2) << ' ' << inv_fact[8] << endl;
    
    dp[0] = 1;
    for(int i = 2; i < (MAXN << 1); i += 2) 
        dp[i] = nCr(i, 2) * dp[i - 2] % MOD;
    
    F0R(p, MAXN) f[p][0] = f[0][p] = 1;

    FOR(p, 1, MAXN) {
        f[p][0] = 1;
        FOR(q, 1, MAXN) f[p][q] = (f[p - 1][q] + 4ll * q * f[p - 1][q - 1]) % MOD;
    }

    return;
}

int main() {
    IOS;
    
    precalc();
    cin >> n >> m;
    
    LL ans = 0;
    F0R(x, n + 1) F0R(y, m + 1) {
        if (n - 2 * x - y < 0 || m - x - 2 * y < 0) continue;
        ans = (ans + (((((nCr(n, 2 * x) * nCr(m, 2 * y) % MOD) * nCr(m - 2 * y, x) % MOD) * nCr(n - 2 * x, y) % MOD) * f[n - 2 * x - y][m - x - 2 * y] % MOD) * dp[2 * x] % MOD) * dp[2 * y] % MOD);
    }

    cout << (ans - 1 + MOD) % MOD;
}

Subtask #1
48.0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 40 ms 71216 KB Output is correct
2 Correct 41 ms 71116 KB Output is correct
3 Correct 41 ms 71208 KB Output is correct
4 Correct 41 ms 71168 KB Output is correct
5 Correct 40 ms 71108 KB Output is correct
6 Correct 42 ms 71204 KB Output is correct
7 Correct 45 ms 71116 KB Output is correct
8 Correct 40 ms 71176 KB Output is correct
9 Correct 40 ms 71156 KB Output is correct
10 Correct 40 ms 71212 KB Output is correct
11 Correct 39 ms 71200 KB Output is correct
12 Correct 41 ms 71216 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 40 ms 71216 KB Output is correct
2 Correct 41 ms 71116 KB Output is correct
3 Correct 41 ms 71208 KB Output is correct
4 Correct 41 ms 71168 KB Output is correct
5 Correct 40 ms 71108 KB Output is correct
6 Correct 42 ms 71204 KB Output is correct
7 Correct 45 ms 71116 KB Output is correct
8 Correct 40 ms 71176 KB Output is correct
9 Correct 40 ms 71156 KB Output is correct
10 Correct 40 ms 71212 KB Output is correct
11 Correct 39 ms 71200 KB Output is correct
12 Correct 41 ms 71216 KB Output is correct
13 Correct 45 ms 71212 KB Output is correct
14 Correct 48 ms 71244 KB Output is correct
15 Correct 75 ms 71148 KB Output is correct
16 Correct 47 ms 71236 KB Output is correct
17 Correct 46 ms 71108 KB Output is correct
18 Correct 50 ms 71216 KB Output is correct
19 Correct 80 ms 71220 KB Output is correct
20 Correct 77 ms 71108 KB Output is correct
21 Correct 60 ms 71216 KB Output is correct
22 Correct 60 ms 71124 KB Output is correct
23 Correct 47 ms 71108 KB Output is correct
24 Correct 100 ms 71112 KB Output is correct
25 Correct 92 ms 71116 KB Output is correct
26 Correct 91 ms 71216 KB Output is correct
27 Correct 96 ms 71204 KB Output is correct