제출 #217945

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
217945		Vimmer	Zapina (COCI20_zapina)	C++14	110 / 110	196 ms	3320 KiB

zapina

#include <bits/stdc++.h>

#define F first
#define S second
#define sz(x) int(x.size())
#define pb push_back
#define N 100005
#define M ll(1e9 + 7)

using namespace std;

typedef long double ld;
typedef long long ll;
typedef short int si;

ll fx(ll a, ll b) {return (a + b) % M;}

ll mx(ll a, ll b) {return (a * b) % M;}

ll binpow(ll a, ll b)
{
    if (b == 0) return 1ll;

    ll s = binpow(a, b / 2);

    if (b % 2) return mx(mx(s, s), a);

    return mx(s, s);
}

ll dp[351][351][2];

ll fact[351], binnom[351][351];

ll calc(ll n, ll k)
{
    if (k == 0) return 1;

    return mx(fact[n], binpow(mx(fact[n - k], fact[k]), M - 2));
}

int main()
{
    ios_base::sync_with_stdio(0); istream::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    int n;

    cin >> n;

    fact[0] = 1;

    fact[1] = 1;

    for (ll i = 2; i <= n; i++) fact[i] = mx(fact[i - 1], i);

    for (ll i = 0; i <= n; i++)
      for (ll j = 0; j <= i; j++) binnom[i][j] = calc(i, j);

    dp[0][n][0] = 1;

    for (ll i = 2; i <= n; i++) dp[0][n - i][0] = binnom[n][i];

    dp[0][n - 1][1] = binnom[n][1];

    for (int i = 0; i < n - 1; i++)
      for (int j = 0; j <= n; j++)
        for (int f = 0; f <= 1; f++)
          {
              for (int u = 0; u <= j; u++)
              {
                if (u == i + 2) dp[i + 1][j - u][1] = fx(dp[i + 1][j - u][1], mx(binnom[j][u], dp[i][j][f]));
                     else  dp[i + 1][j - u][f] = fx(dp[i + 1][j - u][f], mx(binnom[j][u], dp[i][j][f]));
              }
        }

    cout << dp[n - 1][0][1] << endl;
}

• Subtask 1: 22 / 22
• Subtask 2: 33 / 33
• Subtask 3: 55 / 55