Submission #311309

#	Time	Username	Problem	Language	Result	Execution time	Memory
311309		jainbot27	Kangaroo (CEOI16_kangaroo)	C++17	100 / 100	39 ms	31616 KiB

kangaroo

#include "iostream"
using namespace std;

const int64_t MOD = 1e9 + 7;
int64_t dp[2001][2001];

int main(){
    int n, a, b;
    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 || i == b) 
                dp[i][j] = (dp[i-1][j] + dp[i-1][j-1]) % MOD;
            else 
                dp[i][j] = (dp[i-1][j+1] * j + dp[i-1][j-1] * (j - (i > a) - (i > b))) % MOD;
        }
    cout << dp[n][1];
}

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