Submission #1117644

#	Time	Username	Problem	Language	Result	Execution time	Memory
1117644		vjudge1	Kangaroo (CEOI16_kangaroo)	C++17	6 / 100	2066 ms	336 KiB

kangaroo

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

#define int long long
#define ld double


const int INF = 1e18;
const int mod = 12345;
const int sz = 1e6 + 5;

bool is_valid(vector < int > cl , int n)
{
    int cnt = 0;
    if(cl[0] > cl[1]) cnt = 1;
    else cnt = 2;
    for(int i = 2;i < n;i++)
    {
        if(cnt & 1){
            if(cl[i] < cl[i - 1]) return false;
        }
        else{
            if(cl[i] > cl[i - 1]) return false;
        }
        cnt++;
    }
    return true;
}

signed main()
{
   ios_base::sync_with_stdio(0);
   cin.tie(0);
   int n , s , f;
   cin >> n >> s >> f;
   vector < int > cl;
   for(int i = 1;i <= n;i++){
    cl.push_back(i);
   }
   int ans = 0;
   while(next_permutation(cl.begin() , cl.end()))
   {
       if(!(cl[0] == s && cl[n - 1] == f)) continue;
       if(is_valid(cl , n))
       {
           ans++;
       }
   }
   cout << ans << endl;
}

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