Submission #540132

#	Time	Username	Problem	Language	Result	Execution time	Memory
540132		doowey	NoM (RMI21_nom)	C++14	9 / 100	1085 ms	1084 KiB

Main

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

#define fi first
#define se second
#define mp make_pair
#define fastIO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

const int N = 2010;
const int MOD = (int)1e9 + 7;
int dp[N][N];
int C[N][N];
int q[N];

void add(int &u, int v){
    u = (u + v) % MOD;
}

int mm[2][10];

ll brute(int n, int m){
    vector<pii> P;
    for(int i = 1; i <= n; i ++ ){
        P.push_back(mp(i, 0));
        P.push_back(mp(i, 1));
    }
    int soln = 0;
    bool ss;
    do{
        for(int i = 0 ; i < P.size(); i ++ ){
            mm[P[i].se][P[i].fi] = i % m;
        }
        ss = true;
        for(int i = 1; i <= n; i ++ ){
            if(mm[0][i] == mm[1][i]) ss = false;
        }
        if(ss) soln ++ ;
    }while(next_permutation(P.begin(), P.end()));
    return soln;
}

int main(){
    fastIO;
    //freopen("in.txt","r",stdin);
    int n, m;
    cin >> n >> m;
    for(int i = 0 ; i <= n; i ++ ){
        C[i][0] = 1;
    }
    for(int i = 0; i < n * 2; i ++ ){
        q[i % m] ++ ;
    }
    for(int i = 1; i <= n; i ++ ){
        for(int j = 1; j <= i; j ++ ){
            C[i][j] = (C[i-1][j-1] + C[i-1][j]) % MOD;
        }
    }
    dp[0][q[0]] = C[n][q[0]];
    int qs = 0;
    ll V, U;
    int full;
    for(int i = 1; i < m ; i ++ ){
        qs += q[i - 1];
        for(int x = 0; x <= n; x ++ ){
            if(dp[i-1][x] == 0) continue;
            for(int y = 0; y <= x && y <= q[i]; y ++ ){
                V = C[x][y];
                full = n - (qs - x) / 2;
                U = C[full][q[i] - y];
                U = (U * 1ll * V) % MOD;
                U = (U * 1ll * dp[i-1][x]) % MOD;
                add(dp[i][(x - y) + (q[i] - y)], U);
            }
        }
    }
    ll pwr = 1ll;
    for(int i = 1; i <= n; i ++ ){
        pwr = (pwr * 2ll) % MOD;
    }
    ll res = (dp[m - 1][0] * 1ll * pwr) % MOD;
    cout << brute(n, m) << "\n";
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'll brute(int, int)':
Main.cpp:34:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |         for(int i = 0 ; i < P.size(); i ++ ){
      |                         ~~^~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:84:8: warning: unused variable 'res' [-Wunused-variable]
   84 |     ll res = (dp[m - 1][0] * 1ll * pwr) % MOD;
      |        ^~~

• Subtask 1: 9 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 13
• Subtask 4: 0 / 18
• Subtask 5: 0 / 48