Submission #498040

#	Time	Username	Problem	Language	Result	Execution time	Memory
498040		andrei_boaca	Amusement Park (CEOI19_amusementpark)	C++14	100 / 100	1057 ms	2832 KiB

amusementpark

#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
const ll mod=998244353,inv2=499122177;
int n,m,bits[25],lg,cmask[25];
int dp[(1<<18)+5];
int B[25];
bool isthere[1000006];
ll gethash(ll x, ll y)
{
    ll rez=(x<<18);
    rez+=y;
    return rez;
}
bool good[(1<<18)+5],edge[25][25];
int bit[(1<<18)+5];
int main()
{
    cin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int a,b;
        cin>>a>>b;
        cmask[a]+=(1<<(b-1));
        cmask[b]+=(1<<(a-1));
        a--;
        b--;
        edge[a][b]=edge[b][a]=1;
    }
    for(int mask=0;mask<(1<<n);mask++)
    {
        for(int a=0;a<n;a++)
            if((mask>>a)&1)
                for(int b=0;b<n;b++)
                    if((mask>>b)&1)
                        good[mask]|=edge[a][b];
        good[mask]= !good[mask];
        if(mask==0)
            bit[mask]=-1;
        else
        {
            int lsb=(mask&(-mask));
            bit[mask]=bit[mask^lsb]*(-1);
        }
    }
    for(int mask=0;mask<(1<<n);mask++)
    {
        if(good[mask])
        {
            dp[mask]=1;
            continue;
        }
        for(int submask=mask;submask>0;submask=(submask-1)&mask)
            if(good[submask]&&submask!=mask)
                dp[mask]=(dp[mask]+bit[submask]*dp[mask^submask]+mod)%mod;
    }
    ll ans=dp[(1<<n)-1];
    ans=(ans*m)%mod;
    ans=(ans*inv2)%mod;
    cout<<ans;
    return 0;
}

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