Submission #936095

#	Time	Username	Problem	Language	Result	Execution time	Memory
936095		a_l_i_r_e_z_a	Amusement Park (CEOI19_amusementpark)	C++17	100 / 100	1413 ms	2928 KiB

amusementpark

// In the name of God
// Hope is last to die

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

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define pb push_back
#define int long long
#define S second
#define F first
#define mp make_pair
#define smax(x, y) (x) = max((x), (y))
#define smin(x, y) (x) = min((x), (y))
#define all(x) (x).begin(), (x).end()

const int maxn = 18;
const int inf = 1e9 + 7, mod = 998244353;
int n, m, adj[maxn], dp[1ll << maxn];
bool is_val[1ll << maxn];

int32_t main()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n >> m;
    for(int i = 0; i < m; i++){
        int u, v; cin >> u >> v;
        u--, v--;
        adj[u] += 1ll << v;
        adj[v] += 1ll << u;
    }
    is_val[0] = 1;
    for(int mask = 1; mask < (1ll << n); mask++){
        int i = __builtin_ctz(mask);
        if(is_val[mask - (1ll << i)] && (adj[i] & mask) == 0) is_val[mask] = 1;
    }
    dp[0] = 1;
    for(int mask = 1; mask < (1ll << n); mask++){
        for(int sm = mask; sm; sm = mask & (sm - 1)){
            if(is_val[sm]){
                if(__builtin_parity(sm)){
                    dp[mask] = (1ll * dp[mask] + dp[mask - sm]) % mod;
                }
                else{
                    dp[mask] = (1ll * dp[mask] - dp[mask - sm] + mod) % mod;
                }
            }
        }
    }
    int ans = (dp[(1ll << n) - 1] * m) % mod;
    cout << (ans * ((mod + 1) / 2)) % mod << '\n';

    return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 23 / 23
• Subtask 4: 21 / 21
• Subtask 5: 37 / 37