Submission #543115

#	Time	Username	Problem	Language	Result	Execution time	Memory
543115		iulia13	Kangaroo (CEOI16_kangaroo)	C++14	0 / 100	17 ms	16360 KiB

kangaroo

#include <bits/stdc++.h>

using namespace std;
const int N = 1005;
#define ll long long
const ll mod = 1e9 + 7;
void sum(ll &a, ll b)
{
    a += b;
    if (a >= mod)
        a -= mod;
}
ll dp[N][N];
int main()
{
    freopen ("kangaroo.in", "r", stdin);
    freopen ("kangaroo.out", "w", stdout);
    ll n, cs, cf;
    cin >> n >> cs >> cf;
    dp[1][1] = 1;
    for (ll i = 1; i <= n; i++)
        for (ll j = 1; j <= n; j++)
        {
            if (i == cs || i == cf)
            {
                sum(dp[i][j], dp[i - 1][j - 1]);
                sum(dp[i][j], dp[i - 1][j]);
                continue;
            }
            sum(dp[i][j], dp[i - 1][j + 1] * j % mod);
            sum(dp[i][j], (dp[i - 1][j - 1] * ((j - 2) + (i < cs) + (i < cf))) % mod);
        }
    cout << dp[n][1];
    return 0;
}

Compilation message (stderr)

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:16:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |     freopen ("kangaroo.in", "r", stdin);
      |     ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
kangaroo.cpp:17:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |     freopen ("kangaroo.out", "w", stdout);
      |     ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 6
• Subtask 2: 0 / 30
• Subtask 3: 0 / 15
• Subtask 4: 0 / 49