Submission #474800

#	Time	Username	Problem	Language	Result	Execution time	Memory
474800		SirCovidThe19th	Kangaroo (CEOI16_kangaroo)	C++17	100 / 100	38 ms	31652 KiB

kangaroo

#include <bits/stdc++.h>
using namespace std; 

int n, a, b, md = 1e9 + 7; long long dp[2005][2005];

int main(){
    cin >> n >> a >> b; dp[0][0] = 1;
    for (int i = 1; i <= n; i++){
        for (int j = 1; j <= n; j++){
            if (i == a or i == b) 
                dp[i][j] = (dp[i - 1][j] + dp[i - 1][j - 1]) % md;
            else 
                dp[i][j] = (dp[i - 1][j + 1] * j + dp[i - 1][j - 1] * (j - (i > a) - (i > b))) % md;
        }
    }
    cout<<dp[n][1]<<endl;
}

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