Submission #782029

#	Time	Username	Problem	Language	Result	Execution time	Memory
782029		Lobo	Amusement Park (CEOI19_amusementpark)	C++17	100 / 100	1313 ms	223032 KiB

amusementpark

#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
const int maxn = 18;
const int mod = 998244353;

int n, m, g[maxn];
unordered_map<int,int> dp[(1<<maxn)];

int opos(int x) {
    return (1<<n)-1-x;
}

void solve() {
    cin >> n >> m;

    for(int i = 1; i <= m; i++) {
        int u,v; cin >> u >> v; u--; v--;
        g[u]+= (1<<v);
        g[v]+= (1<<u);
    }

    dp[0][(1<<n)-1] = 1;
    for(int use = 0; use < (1<<n)-1; use++) {
        for(auto X : dp[use]) {
            int nxt = X.fr;
            int cnt = X.sc;

            for(int i = 0; i < n; i++) {
                if(((1<<i)&nxt) == 0) continue;
                int use1 = use+(1<<i);
                int nxt1 = ((nxt&opos((1<<(i+1))-1))|g[i])&(opos(use1));
                dp[use1][nxt1]+= cnt;
                dp[use1][nxt1]%= mod;
            }
        }
    }

    cout << dp[(1<<n)-1][0]*m%mod*((mod+1)/2)%mod << endl;
}
    
int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    int tt = 1;
    // cin >> tt;
    while(tt--) {
        solve();
    }

}

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