Submission #364698

# Submission time Handle Problem Language Result Execution time Memory
364698 2021-02-09T17:38:55 Z Nima_Naderi Tents (JOI18_tents) C++14
100 / 100
284 ms 71472 KB
///In the name of GOD
//#pragma GCC optimize("O2")
#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
const ll MXN = 3e3 + 10;
const ll Mod = 1e9 + 7;
ll power(ll a, ll b){
    return (!b ? 1 : power(a * a % Mod, b / 2) * (b & 1LL ? a : 1) % Mod);
}
ll inv(ll x){
    return power(x, Mod - 2);
}
inline void mkay(ll& x){
    while(x >= Mod) x -= Mod;
}
ll n, m;
ll dp[MXN][MXN], F[MXN], I[MXN];
ll nCr(ll n, ll r){
    if(r < 0 || r > n) return 0;
    return F[n] * I[r] % Mod * I[n - r] % Mod;
}
int main(){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
    F[0] = I[0] = 1;
    for(int i = 1; i < MXN; i ++) F[i] = F[i - 1] * i % Mod;
    I[MXN - 1] = inv(F[MXN - 1]);
    for(int i = MXN - 2; i; i --) I[i] = I[i + 1] * (i + 1) % Mod;
    for(int i = 0; i < MXN; i ++) dp[i][0] = dp[0][i] = 1;
    dp[1][1] = 4 + 1;
    for(int j = 2; j < MXN; j ++){
        dp[j][1] = dp[1][j] = (4 * j + nCr(j, 2) + 1) % Mod;
    }
    for(int i = 2; i < MXN; i ++){
        for(int j = 2; j < MXN; j ++){
            dp[i][j] = (dp[i - 1][j] + nCr(j, 2) * dp[i - 1][j - 2] % Mod);
            dp[i][j] = (dp[i][j] + j * 4 * dp[i - 1][j - 1] % Mod);
            dp[i][j] = (dp[i][j] + j * (i - 1) % Mod * dp[i - 2][j - 1] % Mod);
            mkay(dp[i][j]);
        }
    }
    cin >> n >> m;
    cout << dp[n][m] - 1 << '\n';
    return 0;
}
/*!
    HE'S AN INSTIGATOR,
    ENEMY ELIMINATOR,
    AND WHEN HE KNOCKS YOU BETTER
    YOU BETTER LET HIM IN.
*/
//! N.N
# Verdict Execution time Memory Grader output
1 Correct 254 ms 71276 KB Output is correct
2 Correct 250 ms 71276 KB Output is correct
3 Correct 256 ms 71320 KB Output is correct
4 Correct 264 ms 71404 KB Output is correct
5 Correct 256 ms 71276 KB Output is correct
6 Correct 263 ms 71276 KB Output is correct
7 Correct 256 ms 71296 KB Output is correct
8 Correct 252 ms 71276 KB Output is correct
9 Correct 264 ms 71404 KB Output is correct
10 Correct 251 ms 71276 KB Output is correct
11 Correct 264 ms 71276 KB Output is correct
12 Correct 255 ms 71404 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 254 ms 71276 KB Output is correct
2 Correct 250 ms 71276 KB Output is correct
3 Correct 256 ms 71320 KB Output is correct
4 Correct 264 ms 71404 KB Output is correct
5 Correct 256 ms 71276 KB Output is correct
6 Correct 263 ms 71276 KB Output is correct
7 Correct 256 ms 71296 KB Output is correct
8 Correct 252 ms 71276 KB Output is correct
9 Correct 264 ms 71404 KB Output is correct
10 Correct 251 ms 71276 KB Output is correct
11 Correct 264 ms 71276 KB Output is correct
12 Correct 255 ms 71404 KB Output is correct
13 Correct 253 ms 71404 KB Output is correct
14 Correct 253 ms 71276 KB Output is correct
15 Correct 252 ms 71404 KB Output is correct
16 Correct 253 ms 71472 KB Output is correct
17 Correct 251 ms 71276 KB Output is correct
18 Correct 253 ms 71404 KB Output is correct
19 Correct 254 ms 71404 KB Output is correct
20 Correct 251 ms 71404 KB Output is correct
21 Correct 254 ms 71404 KB Output is correct
22 Correct 250 ms 71276 KB Output is correct
23 Correct 256 ms 71288 KB Output is correct
24 Correct 253 ms 71276 KB Output is correct
25 Correct 254 ms 71360 KB Output is correct
26 Correct 251 ms 71276 KB Output is correct
27 Correct 284 ms 71280 KB Output is correct