제출 #252222

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
252222		Blagojce	Network (BOI15_net)	C++11	0 / 100	1 ms	384 KiB

net

#include <bits/stdc++.h> 
#define fr(i, n, m) for(int i = (n); i < (m); i ++)
#define pb push_back
#define st first
#define nd second
#define pq priority_queue
#define all(x) begin(x), end(x)
#include <time.h>
#include <cmath>

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;

const int i_inf = 1e9;
const ll inf = 1e18;
const ll mod = 1000000007;
const ld eps = 1e-13;
const ld pi  = 3.14159265359;
 
mt19937 _rand(time(NULL));
clock_t timer = clock();
const int mxn = 1e5;

int n;

void solve(){
	cin >> n;
	int deg[n];
	memset(deg, 0, sizeof(deg));
	fr(i, 0, n-1){
		int u, v;
		cin >> u >> v;
		
		--u, --v;
		
		++deg[u];
		++deg[v];
	}
	vector<pii> v;
	int pr = -1;
	fr(i, 0, n){
		if(deg[i] == 1){
			if(pr == -1) pr = i;
			else{
				v.pb({pr, i});
				pr = -1;
			}
		}
	}
	if(pr != -1){
		if(pr == 0) ++pr;
		v.pb({0, pr});
	}
	cout<<v.size()<<endl;
	for(auto u : v) cout<<u.st+1<<' '<<u.nd+1<<endl;
	
	
}

 
int main(){


	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	solve();
}

• Subtask 1: 0 / 18
• Subtask 2: 0 / 45
• Subtask 3: 0 / 37