oj.uz

Submission #649197

# Submission time Handle Problem Language Result Execution time Memory
649197 2022-10-09T15:12:33 Z boris_mihov NoM (RMI21_nom) C++17
0 / 100
 1 ms 332 KB 
#include <algorithm>
#include <iostream>
#include <numeric>
#include <vector>
#include <set>

typedef long long llong;
const int MAXN = 2000 + 10;
const int MOD  = 1e9 + 7;
const int INF  = 1e9;

int n, m;
int fact[MAXN];
int var[MAXN][MAXN];
int comb[MAXN][MAXN];
int dp[2][MAXN][MAXN];
void solve()
{
    for (int i = 0 ; i <= n ; ++i)
    {
        comb[i][0] = 1;
    }

    fact[0] = 1;
    for (int i = 1 ; i <= n ; ++i)
    {
        fact[i] = (1LL * fact[i-1] * i);
    }

    for (int i = 1 ; i <= n ; ++i)
    {
        for (int j = 1 ; j <= i ; ++j)
        {
            comb[i][j] = comb[i-1][j] + comb[i-1][j-1];
            if (comb[i][j] >= MOD) comb[i][j] -= MOD;
        }
    }

    for (int i = 0 ; i <= n ; ++i)
    {
        for (int j = 0 ; j <= i ; ++j)
        {
            var[i][j] = (1LL * comb[i][j] * fact[j]) % MOD; 
        }
    }

    dp[0][0][0] = 1;
    for (int i = 1 ; i <= m ; ++i)
    {
        int len = 2*n / m + (2*n % m >= i-1) - (i == 1);
        for (int zeros = 0 ; zeros <= n ; ++zeros)
        {
            for (int ones = 0 ; ones <= n ; ++ones)
            {
                for (int addOnes = std::max(0, len - ones) ; addOnes <= std::min(len, zeros) ; ++addOnes)
                {
                    dp[i&1][zeros][ones] += (((((1LL * dp[!(i&1)][zeros - addOnes][ones + 2*addOnes - len] * comb[len][addOnes]) % MOD) * var[zeros][addOnes]) % MOD) * var[ones][len - addOnes]) % MOD;
                    if (dp[i&1][zeros][ones] >= MOD) dp[i&1][zeros][ones] -= MOD;
                }
            }
        }
    }

    std::cout << dp[m&1][n][0] << '\n';
}

void read() 
{
    std::cin >> n >> m;
}

void fastIO()
{
    std::ios_base :: sync_with_stdio(0);
    std::cout.tie(nullptr);
    std::cin.tie(nullptr);
}

int main()
{
    fastIO();
    read();
    solve();

    return 0;
}

Subtask #1
0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 328 KB Output is correct
3 Incorrect 1 ms 332 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 328 KB Output is correct
3 Incorrect 1 ms 332 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 328 KB Output is correct
3 Incorrect 1 ms 332 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 328 KB Output is correct
3 Incorrect 1 ms 332 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #5
0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 1 ms 328 KB Output is correct
3 Incorrect 1 ms 332 KB Output isn't correct
4 Halted 0 ms 0 KB -