Submission #593380

#	Time	Username	Problem	Language	Result	Execution time	Memory
593380		Hanksburger	Kangaroo (CEOI16_kangaroo)	C++17	100 / 100	25 ms	31700 KiB

kangaroo

#include <bits/stdc++.h>
using namespace std;
const long long mod=1e9+7;
long long dp[2005][2005];
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n, s, f;
    cin >> n >> s >> f;
    dp[0][0]=1;
    for (int i=1; i<=n; i++)
        for (int j=1; j<=n; j++)
            dp[i][j]=((i==s || i==f)?(dp[i-1][j-1]+dp[i-1][j]):(dp[i-1][j+1]*j+dp[i-1][j-1]*(j-(i>s)-(i>f))))%mod;
    cout << dp[n][1];
    return 0;
}

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