Submission #710467

#	Time	Username	Problem	Language	Result	Execution time	Memory
710467		lukameladze	Kangaroo (CEOI16_kangaroo)	C++14	100 / 100	43 ms	39612 KiB

kangaroo

# include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
#define int long long
#define pii pair <int, int>
#define pb push_back
const int N = 3005, mod = 1e9 + 7;
int t,n,a[N],dp[N][N],cs,cf;
main() {
    std::ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
    cin>>n>>cs>>cf;
    dp[0][0] = 1;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            if (i == cs || i == cf) {
                dp[i][j] = dp[i - 1][j] + dp[i - 1][j - 1]; dp[i][j] %= mod;
            } else {
                dp[i][j] += dp[i - 1][j + 1] * j % mod;
                dp[i][j] += dp[i - 1][j - 1] * (j - (i > cs) - (i > cf)) % mod;
                dp[i][j] %= mod;
            }
        }
    }
    cout<<dp[n][1]<<"\n";
}

Compilation message (stderr)

kangaroo.cpp:10:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   10 | main() {
      | ^~~~

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