Submission #936091

#	Time	Username	Problem	Language	Result	Execution time	Memory
936091		Amirreza_Fakhri	Amusement Park (CEOI19_amusementpark)	C++17	42 / 100	10 ms	4696 KiB

amusementpark

// In the name of the God
#include <bits/stdc++.h>
#define ll long long
#define int long long
#define pb push_back
#define F first
#define S second
#define mp make_pair
#define pii pair <int, int>
#define smin(x, y) (x) = min((x), (y))
#define smax(x, y) (x) = max((x), (y))
#define all(x) (x).begin(), (x).end()
using namespace std;

const int inf = 1e9+7;
const int mod = 998244353;
const int maxn = 18;

int n, m, adj[1<<maxn], ind[1<<maxn], dp[1<<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 v, u; cin >> v >> u;
        adj[1<<(--v)] |= 1<<(--u);
        adj[1<<u] |= 1<<v;
    }
    ind[0] = 1;
    for (int mask = 1; mask < (1<<n); mask++) ind[mask] = ind[mask&(mask-1)]&!(adj[mask&(-mask)]&mask);
    dp[0] = 1;
    for (int mask = 1; mask < (1<<n); mask++) {
        for (int smask = mask; smask; smask = (smask-1)&mask) {
            if (ind[smask]) dp[mask] += (__builtin_parity(smask)*2-1)*dp[mask^smask];
        }
    }
    cout << dp[(1<<n)-1]*m/2 << '\n';
    return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 23 / 23
• Subtask 4: 0 / 21
• Subtask 5: 0 / 37