Submission #1100412

#	Time	Username	Problem	Language	Result	Execution time	Memory
1100412		cow123	Amusement Park (CEOI19_amusementpark)	C++14	0 / 100	1 ms	2388 KiB

amusementpark

#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i = a; i < b;++i)
#define int long long
#define pb push_back
using namespace std;
const int M = 998244353,maxn = 19;
vector<int> V[maxn];
int dp[(1 << maxn)],check[(1 << maxn)];
int fastp(int a,int b){
    int x = 1;
    while(a > 0){
        if(a % 2){
           x*=b;
           x%=M; 
        }
        b*=b;
        b%=M;
        a/=2;
    }
    return x;
}
int32_t main(){
    int n,m;
    cin>>n >>m;
    FOR(i,0,m){
        int x,y;
        cin>>x >>y;
        V[x].pb(y);
        V[y].pb(x);
    }
    FOR(i,0,(1 << n)){
        FOR(j,0,n){
            if((i & (1 << j))){
                for(auto y : V[j + 1]){
                    if(((1 << (y - 1))) & i){
                        check[i] = 1;
                    }
                }
            }
        }
    }
    dp[0] = 1;
    FOR(i,1,(1 << n)){
        for(int j = i; j > 0; j = ((j - 1) & i)){
            dp[i]+=dp[j] * (1 - check[i - j]);
            dp[i]%=M;
        }
        dp[i]+=dp[0] * (1 - check[i]);
        dp[i]%=M;
    }
    cout<<(dp[(1 << n) - 1] * ((fastp(M - 2,2) * m) % M)) % M;
}

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