Submission #1118209

#	Time	Username	Problem	Language	Result	Execution time	Memory
1118209		vjudge1	Kangaroo (CEOI16_kangaroo)	C++17	100 / 100	32 ms	31824 KiB

kangaroo

//Desinged by AzeTurk810 Open source
#include <bits/stdc++.h>
using namespace std;

# define ull unsigned long long
# define hurryup ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
# define endl '\n'
# define pb push_back
# define INF 1e10
# define vbol vector<bool>
# define vint vector<int>
# define ll long long
# define int long long
# define mod 1000000007

signed main()
{
    int n,cs,cf,fixed = 0;
    cin>>n>>cs>>cf;
    vector<vector<int>>dp (n + 3,vector<int>(n + 3,0));
    dp[1][1] = 1;
    for(int i=1;i<=n;i++)
    {
    	if(i == cs || i == cf) fixed++;
    	for(int j = 1;j<i;j++)
    	{
    		if(i == cs || i == cf)
    		{
    			dp[i][j] += dp[i - 1][j];
    			dp[i][j + 1] += dp[i-1][j];
    			dp[i][j]%= mod;
    			dp[i][j + 1]%= mod;
    		}
    		else
    		{
    			dp[i][j - 1] += dp[i - 1][ j] * (j - 1);
    			dp[i][j + 1] += dp[i - 1][j] * (j + 1- fixed);
    			dp[i][j-1] %= mod;
    			dp[i][j + 1] %= mod;
    		}
    	}
    }
    cout<<dp[n][1] % mod<<endl;
}

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