Submission #1117862

#	Time	Username	Problem	Language	Result	Execution time	Memory
1117862		vjudge1	Kangaroo (CEOI16_kangaroo)	C++17	6 / 100	2045 ms	336 KiB

kangaroo

#pragma GCC optimize ("O3")
#include<bits/stdc++.h>
#define ll long long
#define ld long double
#define vl vector<ll>
#define vi vector<int>
#define all(v) v.begin(), v.end()
#define pb push_back
#define iospeed ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
int main()
{
    iospeed
    ll n, cs, cf, i;
    cin >> n >> cs >> cf;
    vl v;
    for(i = 1; i <= n; i++)
        v.pb(i);
    ll res = 0;
    do{
        if(v[0] != cs || v.back() != cf)
            continue;
        ll lst = 1;
        if(v[1] < v[0])
            lst = 0;
        bool ok = true;
        for(i = 2; i < n; i++)
        {
            if((v[i] > v[i-1] && lst) || (v[i] < v[i-1] && !lst)){
                ok = false;
                break;
            }
            lst = 1 - lst;
        }
        if(ok)
            res++;
    }while(next_permutation(all(v)));
    cout << res << "\n";
}

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