Submission #305156

#	Time	Username	Problem	Language	Result	Execution time	Memory
305156		Nayna	Love Polygon (BOI18_polygon)	C++14	21 / 100	372 ms	20204 KiB

polygon

#include <bits/stdc++.h>

using namespace std;

const int mxn = 2e5+5;

typedef long long ll;
typedef unsigned int ui;
typedef unsigned long long ull;
typedef pair<int,int>pii;
typedef pair<int,pii>piii;

#define  sf scanf
#define  pf printf

#define  input freopen("in.txt","r",stdin)
#define  output freopen("out.txt","w",stdout)

#define  inf 1e18
#define  ff first
#define  ss second
#define  MP make_pair
#define  pb push_back
#define  all(v) v.begin(), v.end()
#define  printcase(cases) printf("Case %d:", cases);
#define  Unique(a) a.erase(unique(a.begin(),a.end()),a.end())
#define  FAST  ios_base::sync_with_stdio(0);cout.tie(0)
#define  endl printf("\n")
#define  __lcm(a, b) ((a*b)/__gcd(a, b))

map<string,int>mark;
vector<pii>edge;
int vis[30];
int cnt = 0;
vector<int>adj[30];
void clear_all()
{
    for(int i = 0; i < 25; i++) adj[i].clear();
    memset(vis, 0, sizeof vis);
}
void dfs(int u)
{
    vis[u] = 1;
    cnt++;
    for(auto v : adj[u])
    {
        if(vis[v]) continue;
        dfs(v);
    }
}
int main()
{
   // input;
   // output;

    int n;
    scanf("%d", &n);
    int pos = 1;
    for(int i = 0; i < n; i++)
    {
        string a, b;
        cin >> a >> b;

        if(!mark[a]) mark[a] = pos++;
        if(!mark[b]) mark[b] = pos++;

        int u = mark[a];
        int v = mark[b];
        //cout << u << ' ' << v << '\n';

        edge.push_back({u, v});
    }
    if(n&1)
    {
        cout << "-1\n";
        return 0;
    }
    int lim = (1<<n);
    int ans = 50;
    for(int b = 0; b < lim; b++)
    {
        clear_all();
        int ok = true;
        for(int i = 0; i < n; i++)
        {
            int x = b&(1<<i);
            if(!x && edge[i].ff == edge[i].ss) 
            {
                ok = false;
                break;
            }
            if(!x)
            {
                adj[edge[i].ff].push_back(edge[i].ss);
                adj[edge[i].ss].push_back(edge[i].ff);
            }
        }
        if(!ok) continue;
        ok = true;
        for(int i = 1; i <= n; i++) 
        {
            if(!vis[i]) 
            {
                cnt = 0;
                dfs(i);
                if(cnt>2) 
                {
                    ok = false;
                    break;
                } 
            }
        }
        if(ok) 
        {
            int ase = __builtin_popcount(b);
            //cout << b << '\n';
            ans = min(ans, ase);
        }
    }
    cout << ans << '\n';
    return 0;

}

Compilation message (stderr)

polygon.cpp: In function 'int main()':
polygon.cpp:57:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   57 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~

• Subtask 1: 21 / 21
• Subtask 2: 0 / 25
• Subtask 3: 0 / 29
• Subtask 4: 0 / 25