Submission #1214679

#	Time	Username	Problem	Language	Result	Execution time	Memory
1214679		badge881	Zapina (COCI20_zapina)	C++20	110 / 110	195 ms	3288 KiB

zapina

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
const ll Mod = 1e9 + 7;

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

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

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]), Mod - 2));
}

int main()
{
    int n;
    scanf("%d", &n);

    fact[0] = 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 (int i = 0; i < n; 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 + 1)
                        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]));
                }
            }
    printf("%lld\n", dp[n][0][1]);
}

Compilation message (stderr)

zapina.cpp: In function 'int main()':
zapina.cpp:40:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~

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