Submission #434015

#	Time	Username	Problem	Language	Result	Execution time	Memory
434015		AmineTrabelsi	Love Polygon (BOI18_polygon)	C++14	21 / 100	245 ms	9312 KiB

polygon

#include "bits/stdc++.h"
using namespace std;
// Hi 
 
int main(){
    ios::sync_with_stdio(0);cin.tie(0);
    int n;
    cin>>n;
    vector<int> go(n);
    map<string,int> mp;
    int nxt = 0;
    vector<pair<int,int>> edges;
    for(int i=0;i<n;i++){
        string s,t;
        cin>>s>>t;
        int first = 0,second = 0;
        if(mp.find(s) != mp.end()){
            first = mp[s];
        }else{
            first = nxt;
            mp[s] = nxt++;
        }
        if(mp.find(t) != mp.end()){
            second = mp[t];
        }else{
            second = nxt;
            mp[t] = nxt++;
        }
        edges.push_back({first,second});
    }
    vector<int> perm;
    if(n&1){
        cout << -1 << endl;
        return 0;
    }
    auto good = [&](){
        vector<bool> vis(n+1,0);
        for(int i=0;i<n;i++){
            if(go[i] == i)return false;
            if(go[i] != -1){
                if(go[go[i]] != -1 && go[go[i]] != i)return false;
                if(vis[go[i]])return false;
                vis[go[i]] = 1;
            }
        }
        return true;
    };
    int ans = 1000000009;
    for(int i=0;i<(1 << n);i++){
        int cnt = n;
        go.assign(n,-1);
        for(int j=0;j<n;j++){
            if(i & (1<<j)){
                go[edges[j].first] = edges[j].second;
                cnt--;
            }
        }
        /*
        for(auto x:go)cout << x<<" ";
            cout<<'\n';*/
        if(good()){
            /*
            for(auto x:go)cout << x<<" ";
            cout<<'\n';*/
            ans = min(ans,cnt);
        }
    }
    cout << ans << '\n';
    return 0;
}

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