Submission #529212

#	Time	Username	Problem	Language	Result	Execution time	Memory
529212		Mondeus	Kangaroo (CEOI16_kangaroo)	C++17	0 / 100	1 ms	332 KiB

kangaroo

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <string>
#include <cstring>
#include <iomanip>
#include <map>
#include <queue>
using namespace std;
const int maxn = 2e3;
int n,s,e;
long long dp[maxn+5][maxn+5];
const int MOD = 1e9+7;
void solve()
{
    cin >> n >> s >> e;
    dp[1][1] = 1;
    for(int i = 1; i < n; i++)
    {
        for(int j = 1; j <= i; j++)
        {
            if(i + 1 == s || i + 1 == e) dp[i+1][j+1] = (dp[i+1][j+1] + dp[i][j]) % MOD, dp[i+1][j] = (dp[i+1][j] + dp[i][j]) % MOD;
            else
            {
                dp[i+1][j+1] = (dp[i+1][j+1] + (j - (i >= s) - (i >= e)) * dp[i][j]) % MOD;
                dp[i+1][j-1] = (dp[i+1][j-1] + (j - 1) * dp[i][j]) % MOD;
            }
        }
    }
    cout << dp[n][1];
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    solve();
    return 0;
}

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