Submission #889197

#	Time	Username	Problem	Language	Result	Execution time	Memory
889197		Alora	Logičari (COCI21_logicari)	C++17	20 / 110	30 ms	7004 KiB

Main

#include <bits/stdc++.h>
#define Alora "cownav"
#define fi(i,a,b) for(int i = a; i <= b; i++)
#define fid(i,a,b) for(int i = a; i >= b; i--)
#define ll long long
#define f first
#define se second
#define pii pair<int, int>
#define getbit(i, j) ((i >> j) & 1)
#define all(v) v.begin(), v.end()
#define pb push_back
#define maxn 100005
const int M = 1e9 + 7;
using namespace std;
int n, xd[maxn], res = 1e9, ok, ok1 = 1;
vector <int> g[maxn];

void sub1(){
    if(n % 4 == 0) cout << n/2;
    else cout << -1;
    exit(0);
}

void sub2(){
    fi(tt, 1, (1 << n) - 1){
        int cnt = __builtin_popcount(tt);
        fi(i, 0, n - 1) xd[i + 1] = getbit(tt, i);
        ok = 1;
        fi(u, 1, n){
            int sl = 0;
            for(auto v: g[u]) sl += xd[v];
            if(sl != 1) {ok = 0; break;}
        }
        if(ok) res = min(res, cnt);
    }
    if(res == 1e9) cout << -1;
    else cout << res;
    exit(0);
}
int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(NULL);
	if(fopen(Alora".inp", "r")){
    freopen(Alora".inp", "r", stdin);
    freopen(Alora".out", "w", stdout);}
    cin >> n;
    fi(i, 1, n){
        int u, v; cin >> u >> v;
        g[u].pb(v); g[v].pb(u);
    }
    fi(i, 1, n) if(g[i].size() != 2) {ok1 = 0; break;}
    if(ok1) sub1();
    if(n <= 20) sub2();

    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:44:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |     freopen(Alora".inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:45:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |     freopen(Alora".out", "w", stdout);}
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 40
• Subtask 4: 0 / 50