Submission #495327

#	Time	Username	Problem	Language	Result	Execution time	Memory
495327		VladM	Kangaroo (CEOI16_kangaroo)	C++14	6 / 100	1 ms	460 KiB

kangaroo

#include <bits/stdc++.h>

using namespace std;

#define modulo 1000000007

long long n, dp[2007][2007], f, cs, cf;

int main()
{
    cin>>n>>cs>>cf;
    dp[0][0]=1;
    for(long long i=1; i<=n; i++){
        for(long long j=1; j<=n; j++){
            if(i==cs || i==cf){
                dp[i][j]=(dp[i-1][j-1]+dp[i-1][j])%modulo;
                continue;
            }
            if(i<cs) dp[i][j]=j*(dp[i-1][j-1]+dp[i-1][j+1]);
            else if(i<cf) dp[i][j]=dp[i-1][j-1]*(j-1)+dp[i-1][j+1]*j;
            else dp[i][j]=dp[i-1][j-1]*(j-2)+dp[i-1][j+1]*j;
            dp[i][j]%=modulo;
        }
    }
    cout<<dp[n][1];
    return 0;
}

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