Submission #781128

#	Time	Username	Problem	Language	Result	Execution time	Memory
781128		definitelynotmee	Amusement Park (CEOI19_amusementpark)	C++17	63 / 100	3069 ms	6484 KiB

amusementpark

#include<bits/stdc++.h>
#define ff first
#define ss second
#define all(x) x.begin(), x.end()
using namespace std;
using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
template<typename T>
using matrix = vector<vector<T>>;
const ll MOD = 998244353;


int main(){
    cin.tie(0)->sync_with_stdio(0);

    int n, m;
    cin >> n >> m;

    vector<int> adj(n);

    for(int i = 0; i < m; i++){
        int a, b;
        cin >> a >> b;
        a--, b--;
        adj[a]+=1<<b;
    }

    vector<ll> incomp(1<<n);

    for(int i = 0; i < (1<<n); i++){
        int ok = 0;
        for(int j = 0; j < n; j++){
            if((1<<j)&i){
                ok|=adj[j];
            }
        }
        
        incomp[i] = !bool(ok&i);
        // cerr << bitset<4>(ok) << ' ' << bitset<4>(i) << "->" << incomp[i] << '\n';
    }

    vector<ll> sum(1<<n), dp(1<<n);

    dp[0] = 1;

    array<ll,2> parity = {MOD-1,1};
    vector<int> cur;

    auto calc =[&](int i, int taken, int cursum, int sub, int mask, auto calc){
        if(i == cur.size()){
            if(!taken)
                return;
            const int comp = mask^sub;
            dp[mask]+=parity[taken&1]*dp[comp];
            sum[mask]+=parity[taken&1]*(cursum*dp[comp]%MOD+sum[comp]);
            dp[mask]%=MOD;
            sum[mask]%=MOD;
            // cerr << i << ' ' << taken << ' ' << cursum << ' ' << bitset<4>(sub) << ' ' << bitset<4>(mask) << '\n';
            // cerr << "=> " << parity[taken&1]*dp[comp] << ' ' << parity[taken&1]*(cursum*dp[comp]%MOD+sum[comp]) << '\n';
            return;
        }
        const int id = cur[i];
        if(incomp[sub|(1<<id)]){
            calc(i+1,taken+1,cursum+__builtin_popcount(adj[id]&mask),sub|(1<<id),mask,calc);
        }
        calc(i+1,taken,cursum,sub,mask,calc);
    };

    for(int mask = 1; mask < (1<<n); mask++){
        cur.clear();
        for(int j = 0 ; j < n; j++){
            if(mask&(1<<j))
                cur.push_back(j);
        }
        calc(0,0,0,0,mask,calc);
        // cerr << "dp[" << bitset<4>(mask) << "] = " << dp[mask] << '\n';
        // cerr << "sum[" << bitset<4>(mask) << "] = " << sum[mask] << '\n';
    }

    cout << sum[(1<<n)-1] << '\n';

}

Compilation message (stderr)

amusementpark.cpp: In instantiation of 'main()::<lambda(int, int, int, int, int, auto:23)> [with auto:23 = main()::<lambda(int, int, int, int, int, auto:23)>]':
amusementpark.cpp:76:31:   required from here
amusementpark.cpp:51:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   51 |         if(i == cur.size()){
      |            ~~^~~~~~~~~~~~~

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