Submission #1294227

#	Time	Username	Problem	Language	Result	Execution time	Memory
1294227		ezim1234	Kangaroo (CEOI16_kangaroo)	C++20	6 / 100	2095 ms	572 KiB

kangaroo

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

#define all(v) v.begin(), v.end()
#define yes cout << "Yes" << "\n"
#define no cout << "No" << "\n"
#define pb push_back
#define F first
#define S second

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
typedef pair <int, int> pii;
typedef vector <pii> vii;
typedef vector <ll> vi;

template<typename T>
void read(vector<T>& v) {
    for (auto &x : v) cin >> x;
}

template<typename T>
void print(const vector<T>& v) {
    for (auto &x : v) cout << x << ' ';
    cout << "\n";
}
int f, s;
int n;
const ll MAX = 1e6 + 5;
const ll MOD = 1e9 + 7;

void solve() {
    int n, s, f;
    cin >> n >> s >> f;
    int say = 0;
    vi a;
    for (int i = 1; i <= n; i++) {
        a.pb(i);
    }
    do {
        bool ok = true;
        if (a[0] != s || a.back() != f) {
            ok = false;
        }
        for (int i = 1; i < a.size() - 1; i++) {
            if (a[i] > a[i + 1] && a[i] < a[i - 1]) {
                ok = false;
            }
            if (a[i] < a[i + 1] && a[i] > a[i - 1]) {
                ok = false;
            }
        }
        if (ok) {
            say++;
        }
        say = say % MOD;
    } while (next_permutation(all(a)));
    cout << say << '\n';
}
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int t = 1;
    //cin >> t;
    for (int i = 1; i <= t; i++) {
        solve();
    }
}

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