Submission #895895

#	Time	Username	Problem	Language	Result	Execution time	Memory
895895		magician	Amusement Park (CEOI19_amusementpark)	C++14	19 / 100	2 ms	604 KiB

amusementpark

#include<bits/stdc++.h>
#define FORU(i, a, b) for(int i = (a), _b = (b); i <= _b; i++)
#define MASK(x) (1 << (x))
#define BIT(x, i) (((x) >> (i)) & 1)
#define TASK "AMUSEMENTPARK"
#define fi first
#define se second
using namespace std;

const int NMAX = 20, MMAX = 200;
int N, M;
pair<int, int> e[MMAX];
vector<int> adj[NMAX];

namespace subtask2 {
        bool is_sub(void) {
                return N <= 6;
        }
        int vis[NMAX];
        bool dfs(int u, int mask) {
                vis[u] = 1;
                for(int id : adj[u]) {
                        int v = e[id].fi + e[id].se - u;
                        if(!BIT(mask, id - 1) && u == e[id].se) continue;
                        if(BIT(mask, id - 1) && u == e[id].fi) continue;
                        if(vis[v] == 1) return false;
                        if(vis[v] == 0) if(!dfs(v, mask)) return false;
                }
                vis[u] = 2;
                return true;
        }
        bool chk(int mask) {
                FORU(i, 1, N) vis[i] = 0;
                FORU(i, 1, N)
                        if(vis[i] == 0) if(!dfs(i, mask)) return false;
                return true;
        }
        void sol(void) {
                int ans = 0;
                FORU(mask, 0, MASK(M) - 1) {
                        if(chk(mask)) {
                                ans += __builtin_popcount(mask);
                        }
                }
                cout << ans;
                return;
        }
}

int main(void) {
        ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
        if(fopen(TASK".INP", "r")) {
                freopen(TASK".INP", "r", stdin);
                freopen(TASK".OUT", "w", stdout);
        }
        cin >> N >> M;
        FORU(i, 1, M) {
                cin >> e[i].fi >> e[i].se;
                adj[e[i].fi].push_back(i);
                adj[e[i].se].push_back(i);
        }
        if(subtask2::is_sub()) return subtask2::sol(), 0;
}

Compilation message (stderr)

amusementpark.cpp: In function 'int main()':
amusementpark.cpp:53:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |                 freopen(TASK".INP", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
amusementpark.cpp:54:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   54 |                 freopen(TASK".OUT", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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