Submission #767604

#	Time	Username	Problem	Language	Result	Execution time	Memory
767604		shezitt	Logičari (COCI21_logicari)	C++14	20 / 110	137 ms	5728 KiB

Main

#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define ld long double
#define gcd(a, b) __gcd(a, b)
#define lcm(a,b) a*b/gcd(a,b)
#define pb push_back
#define ii pair<int,int>
#define vi vector<int>
#define vii vector<pair<int,int>>
#define F first
#define S second
#define sz(x) (int)x.size()
#define fast ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define fore(a, b, c) for(int a=b; a<c; ++a)
#define all(x) x.begin(), x.end()
#define endl '\n';

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#define dbg(x...) cerr << "[" << #x << "] = ["; _print(x)
#define raya cerr << "==========================" << endl;

const double EPS = 1e-7;
const double PI = acos(-1);
const int MOD = 1e9+7;  
int TC = 1;

const int N = 1e5+5;
vi adj[N];

int main(){
    fast;
    int n;
    cin >> n;
    fore(i, 0, n){
        int u, v;
        cin >> u >> v;
        u--;
        v--;
        adj[u].pb(v);
        adj[v].pb(u);
    }
    bool flag = 1;
    fore(i, 0, n){
        flag &= sz(adj[i]) == 2;
    }
    if(flag){
        if(n%4 == 0){
            cout << n/2;
        } else {
            cout << -1;
        }
        return 0;   
    }
    int ans = 1e9;
    vector<bool> blue(n);
    auto check = [&]() -> bool {
        bool ok = 1;
        int r;
        for(int u=0; u<n; ++u){
            r = 0;
            for(int v : adj[u]){
                if(blue[v]){
                    r++;
                }
            }
            ok &= r == 1;
        }
        return ok;
    };  
    for(int mask=0; mask<(1<<n); ++mask){
        blue.assign(n, 0);
        for(int i=0; (1<<i)<=mask; ++i){
            if((1<<i) & mask){
                blue[i] = 1;
            }
        }
        if(check()){
            ans = min(ans, __builtin_popcount(mask));
        }
    }
    cout << (ans == 1e9 ? -1 : ans);
}
 

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