Submission #862820

#	Time	Username	Problem	Language	Result	Execution time	Memory
862820		maks007	Love Polygon (BOI18_polygon)	C++14	0 / 100	2092 ms	15936 KiB

polygon

//Bismi Allah
#include "bits/stdc++.h"

using namespace std;

signed main () {
	// ios::sync_with_stdio(0);
	// cin.tie(0); cout.tie(0);
	int n, ans = 1e9;
	cin >> n;
	vector <int> who(n, -1), used(n, 0);
	map <string,int> mp;
	function<void(int,int)> f=[&](int numUsed, int cnt) {
		if(numUsed == n) {
			ans = min(ans, cnt);
			return;
		}
		for(int i = 0; i < n; i ++) {
			if(used[i] == 1) continue;
			for(int j = i + 1; j < n; j ++) {
				if(used[j] == 1) continue;
				int newcnt = cnt;
				if(who[i] != j) newcnt ++;
				if(who[j] != i) newcnt ++;
				used[i] = 1;
				used[j] = 1;
				f(numUsed + 2, newcnt); 
				used[i] = 0;
				used[j] = 0;
			}
		}
	};
	int cnt = 0;
	for(int i = 0; i < n; i ++) {
		string u, v;
		cin >> u >> v;
		if(mp.count(u) == 0) mp[u] = mp.size();
		if(mp.count(v) == 0) mp[v] = mp.size();
		if(mp[u] == mp[v]) cnt ++;
		who[mp[u]] = mp[v];
	}
	if(n % 2 == 1) {
		cout << "-1";
		return 0;
	}
	f(0,0);
	cout << ans;
	return 0;
}

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