Submission #683719

#	Time	Username	Problem	Language	Result	Execution time	Memory
683719		aSSSd	Logičari (COCI21_logicari)	C++14	20 / 110	131 ms	3020 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define in ({int x=0;int c=getchar(),n=0;for(;!isdigit(c);c=getchar()) n=(c=='-');for(;isdigit(c);c=getchar()) x=x*10+c-'0';n?-x:x;})
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int l,int r)
{
    return l+rng()%(r-l+1);
}
#define fasty ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define forinc(x,a,b) for(int x=a;x<=b;x++)
#define fordec(x,a,b) for(int x=a;x>=b;x--)
#define forv(a,b) for(auto&a:b)
#define fi first
#define se second
#define pb push_back
#define ll long long
#define mt make_tuple
#define all(a) a.begin(),a.end()
#define reset(f,x) memset(f,x,sizeof(f))
#define getbit(x,i) ((x>>(i))&1)
#define batbit(x,i) (x|(1ll<<(i)))
#define tatbit(x,i) (x&~(1<<(i)))
#define gg exit(0);
#define int long long
#define ii pair<int,int>
const int N = 1e5 + 100;
int n;
int cnt[22];
ii edge[N];
main()
{
    fasty;
    cin >> n;
    forinc(i,1,n)
    {
        int u,v;
        cin >> u >> v;
        edge[i] = {u,v};
    }
    if(n<=20)
    {
        int res=1e8;
        int lim=(1<<n)-1;
        forinc(mask , 0 , lim)
        {
            memset(cnt,0,sizeof cnt);
            forinc(i,1,n)
            {
                int u = edge[i].fi;
                int v = edge[i].se;
                if(getbit(mask , u-1)) cnt[v]++;
                if(getbit(mask,v-1)) cnt[u]++;
            }
            int ok=1;
            forinc(i,1,n)
            {
                if(cnt[i] != ok)
                {
                    ok=0;
                    break;
                }
            }
            int sl = __builtin_popcount(mask);
            if(ok) res = min(res , sl);
        }
        if(res>=1e8)
        {
            cout << -1;
            return 0;
        }
        cout << res;
        return 0;
    }
    if(n%4 == 0 )
    {
        cout << n/2;
        return 0;
    }
    cout << -1;

}

Compilation message (stderr)

Main.cpp:31:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   31 | main()
      | ^~~~

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