Submission #928245

#	Time	Username	Problem	Language	Result	Execution time	Memory
928245		vjudge1	Amusement Park (CEOI19_amusementpark)	C++17	0 / 100	2 ms	4440 KiB

amusementpark

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define ent "\n"

const int maxn = 1e6 + 100;
const ll INF = (ll)1e18 + 100;
const int MOD = 998244353;
const int maxl = 20;

int n, m;
int f[maxl][maxl];
ll dp[1<<maxl];
ll d[1<<maxl];
int g[maxl];
int sum[1<<maxl];
bool ok[1<<maxl];

void test(){
    cin >> n >> m;
    for(int i = 1; i <= m; i++){
        int a, b;
        cin >> a >> b;
        a--; b--;
        f[a][b] = 1;
        f[b][a] = 2;
        g[a] |= (1<<b);
        g[b] |= (1<<a);
    }
    d[0] = 1;
    for(int x = 0; x < (1<<n); x++){
        int to = (1<<n)-1;
        for(int i = 0; i < n; i++){
            if(x & (1<<i)){
                to &= g[i];
            }
        }
        to ^= to & x;
        for(int y = 0, lg = 0; ; y = (y + (1<<n) - to) & to){
            sum[y] = 0; ok[y] = 1;
            if(y){
                while((1<<(lg+1)) <= y) lg++;
                if(y == (1<<lg)){
                    for(int i = 0; i < n; i++){
                        if(x & (1<<i)){
                            sum[y] += f[i][lg] - 1;
                        }
                    }
                } else{
                    ok[y] = ok[y ^ (1<<lg)];
                    if(g[lg] & y) ok[y] = 0;
                    sum[y] = sum[1<<lg] + sum[y ^ (1<<lg)];
                }
                if(ok[y]){
                    int mask = y | x;
                    dp[mask] = (dp[mask] + sum[y] * d[x] + dp[x]) % MOD;
                    d[mask] = (d[mask] + d[x]) % MOD;
                }
            }
            if(y == to) break;
        }
    }
    cout << dp[(1<<n)-1];
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    #ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif
    int t; t = 1;
    while(t--) test();
}

Compilation message (stderr)

amusementpark.cpp: In function 'int main()':
amusementpark.cpp:72:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |         freopen("input.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
amusementpark.cpp:73:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         freopen("output.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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