Submission #525949

#	Time	Username	Problem	Language	Result	Execution time	Memory
525949		Slavita	Logičari (COCI21_logicari)	C++14	20 / 110	315 ms	6852 KiB

Main

#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
#define ve vector<int>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define pi pair<int,int>
#define all(v) v.begin(),v.end()
#define si(v) (int)v.size()
#define en '\n'
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define ordered_muiltiset tree<int, null_type,less_equal<>, rb_tree_tag,tree_order_statistics_node_update>
using namespace std;
//using namespace __gnu_pbds;
typedef long long ll;
typedef unsigned long long ull;

const int N = 1e5 + 228;
const int big = 1e9;
const ll llbig = 1e18 + 228;
//ordered_set os; // os.order_of_key(4), (*os.find_by_order(5))
int n, m;
int mrk[N];
vector<int> g[N];

bool getbit(int x, int bit){
    assert(bit > 0);
    bit--;
    return (x & (1 << bit)) == (1 << bit);
}

int main(){
    cin >> n;
    for (int i = 1; i <= n; i++){
        int a, b; cin >> a >> b;
        g[a].pb(b);
        g[b].pb(a);
    }

    if (n <= 21){
        int ans = big;
        for (int mask = 1; mask <= (1 << (n + 1)); mask++){
            bool ok = 1; int an = 0;
            for (int i = 1; i <= n; i++) mrk[i] = 0;
            for (int i = 1; i <= n; i++){
                if (!getbit(mask, i)) continue;
                an++;
                mrk[i] = 2;
                for (auto u : g[i]){
                    if (getbit(mask, u)) continue;
                    if (mrk[u]) {ok = 0; break;}
                    mrk[u] = 1;
                }
            }
            for (int i = 1; i <= n; i++) {
                int kol = 0;
                for (auto u : g[i]){
                    if (getbit(mask, u)) kol++;
                }
                if (kol != 1) {ok = 0; break;}
            }
            if (ok){
                ans = min(ans, an);
            }
        }
        if (ans == big) cout << -1; else cout << ans;
    }else{
        if (n % 4 == 0){
            cout << n / 2;
        } else cout << -1;
    }

    return 0;
}
/*
*/

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