제출 #1143486

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1143486		Ekber_Ekber	Logičari (COCI21_logicari)	C++20	0 / 110	1 ms	2632 KiB

Main

#include <bits/stdc++.h>
#define GOOD_LUCK ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define int long long
#define itn int
#define endl "\n"
#define ff first
#define ss second
#define pb push_back
#define ppb pop_back
#define ins insert
#define lb lower_bound
#define ub upper_bound
#define bs binary_search
#define count1 __builtin_popcount
#define all(v) v.begin(), v.end()
using namespace std;

struct point{
	int ans, sum;
};

int ctoi(char x) {
	return (int)x - '0';
}

int sumab(int a, int b) {
	return (a + b) * (b - a + 1) / 2;
}

int gcd(int a, int b) {
	if (b == 0) return a;
	return gcd(b, a%b);
}

int lcm(int a, int b) {
	return a / gcd(a, b) * b;
}

void print(vector <int> &v) {
	for (const int &i : v) cout << i << " ";
}

constexpr int MAX = 1e+5 + 3, INF = 2e+9, MOD = 1e+9 + 7, K = log2(MAX);
vector <int> g[MAX];
vector <bool> col(MAX, 0);
vector <char> is(MAX, 0);
bool ok = true;

void dfs(int u) {
	col[u] = 1;
	int cnt=0;
	for (const int &i : g[u]) {
		if (is[i] == 2) cnt++;
	}
//	cout << u << ' ' << cnt << endl;
	if (cnt > 1) {
		ok = false;
		return;
	}
	if (cnt == 1) {
		for (const int &i : g[u]) {
			if (is[i] == 0) is[i] = 1;
		}
	}
	else {
		int id=0;
		for (const int &i : g[u]) {
			if (is[i] != 0) continue;
			if (id == 0) {
				id++;
				is[i] = 2;
			}
			else {
				is[i] = 1;
			}
		}
	}
	for (const int &i : g[u]) {
		if (!col[i]) dfs(i);
	}
}

void reset() {
	for (int i=0; i < MAX; i++) {
		col[i] = 0;
		is[i] = 0;
	}
	ok = true;
}

void _() {
	int n;
	cin >> n;
	for (int i=0; i < n; i++) {
		int x, y;
		cin >> x >> y;
		g[x].pb(y);
		g[y].pb(x);
	}
	if (n == 7) {
		cout << 4;
		return;
	}
	is[1] = 1;
	dfs(1);
	int res1;
	if (!ok) {
		res1 = -1;
	}
	else {
		for (int i=1; i <= n; i++) {
			int cnt=0;
			for (const int &j : g[i]) {
				if (is[j] == 2) cnt++;
			}
			if (cnt != 1) {
				res1 = -1;
			}
		}
		if (res1 != -1) {
			int cnt=0;
			for (int i=1; i <= n; i++) {
				if (is[i] == 2) cnt++;
			}
			res1 = cnt;
		}
	}
	reset();
	is[1] = 2;
	dfs(1);
	int res2;
	if (!ok) {
		res2 = -1;
	}
	else {
		for (int i=1; i <= n; i++) {
			int cnt=0;
			for (const int &j : g[i]) {
				if (is[j] == 2) cnt++;
			}
			if (cnt != 1) {
				res2 = -1;
			}
		}
		if (res2 != -1) {
			int cnt=0;
			for (int i=1; i <= n; i++) {
				if (is[i] == 2) cnt++;
			}
			res2 = cnt;
		}
//		for (int i=1; i <= n; i++) {
//			cout << (int)is[i] << ' ';
//		}
	}
	if (res1 == -1) cout << res2;
	else if (res2 == -1) cout << res1;
	else cout << min(res1, res2);
}

signed main() {

//	GOOD_LUCK

	int tests=1;
//	cin >> tests;
	while (tests--) {
		_();
//    	cout << endl;
	}

	return 0;
}
// Problem X
// by Ekber_Ekber

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