Submission #865952

#	Time	Username	Problem	Language	Result	Execution time	Memory
865952		Requiem	Amusement Park (CEOI19_amusementpark)	C++17	100 / 100	1269 ms	3448 KiB

amusementpark

#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define fast ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#define MOD 998244353
#define INF 1e18
#define fi first
#define se second
#define endl "\n"
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define FORD(i,a,b) for(int i=a;i>=b;i--)
#define sz(a) ((int)(a).size())
#define pi 3.14159265359
#define TASKNAME "amusepark"
template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }
using namespace std;
typedef pair<int,int> ii;
typedef pair<int,ii> iii;
typedef vector<int> vi;
const int MAXN = 3e2 + 9;
ii edge[MAXN];
int n,m,ans=0;
int pos[MAXN];
int prep[MAXN];
int N[MAXN];
void add(int &a,int b){
    a += b;
    if (a>=MOD) a-=MOD;
}
void sub(int &a,int b){
    a -= b;
    if (a < 0) a += MOD;
}
int dp[(1<<19)];
bool independent[(1<<19)];
int power(int a,int b){
    int res = 1;
    while(b>0){
        if (b&1) res = (res * a) %MOD;
        b>>=1;
        a = (a * a) % MOD;
    }
    return res;
}
main()
{
    fast;
   //  freopen(TASKNAME".inp","r",stdin);
   //  freopen(TASKNAME".out","w",stdout);
    cin>>n>>m;
    for(int i=1;i<=m;i++){
        cin>>edge[i].fi>>edge[i].se;
//        edge[i].fi--;
//        edge[i].se--;
        N[edge[i].se-1] |= (1<<(edge[i].fi-1));
        N[edge[i].fi-1] |= (1<<(edge[i].se-1));
    }
    vector<int> bit;
    for(int i=1;i<(1<<n);i++){
        bit.clear();
        for(int j=0;j<n;j++){
            if (i&(1<<j)){
               bit.pb(j);
            }
        }
        independent[i] = true;
        for(int j=0;j<bit.size();j++){
            for(int k=0;k<bit.size();k++){
                if (N[bit[j]] & (1<<bit[k])){
                    independent[i] = false;
                }
            }
        }
    }
    dp[0] = 1;

    for(int i=1;i<(1<<n);i++){
        for(int j=i;j>0;j=(j-1)&i){
            int numbit = __builtin_popcount(j);
            if (independent[j]){
                if (numbit & 1) add(dp[i],dp[i^j]);
                else sub(dp[i],dp[i^j]);
            }
        }
    }
    cout<<((dp[(1<<n)-1] * m)%MOD * power(2,MOD-2))%MOD<<endl;
}

Compilation message (stderr)

amusementpark.cpp:46:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   46 | main()
      | ^~~~
amusementpark.cpp: In function 'int main()':
amusementpark.cpp:68:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |         for(int j=0;j<bit.size();j++){
      |                     ~^~~~~~~~~~~
amusementpark.cpp:69:26: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   69 |             for(int k=0;k<bit.size();k++){
      |                         ~^~~~~~~~~~~

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