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답안 #252223

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
252223 2020-07-24T22:18:50 Z Blagojce Network (BOI15_net) C++11
0 / 100
 8 ms 12160 KB 
#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 = 5e5;

int n;
vector<int> g[mxn];
vector<int> v;
void dfs(int u, int p){
	for(auto e : g[u]){
		if(e == p) continue;
		dfs(e, u);
	}
	if((int)g[u].size() == 1){
		v.pb(u);
	}
}

void solve(){
	cin >> n;
	fr(i, 0, n-1){
		int u, v;
		cin >> u >> v;
		
		--u, --v;
		g[u].pb(v);
		g[v].pb(u);
	}
	dfs(0, 0);
	vector<pii> ans;
	for(int i = 1; i < (int)v.size()-1; i += 2){
		ans.pb({v[i], v[i+1]});
	}
	ans.pb({v[0], v.back()});
	
	cout<<ans.size()<<endl;
	
	for(auto u : ans) cout<<u.st+1<<' '<<u.nd+1<<endl;
	
}

 
int main(){


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

Subtask #1
0 / 18.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 12088 KB Output is correct
2 Correct 6 ms 12160 KB Output is correct
3 Correct 7 ms 12032 KB Output is correct
4 Correct 7 ms 12032 KB Output is correct
5 Correct 6 ms 12032 KB Output is correct
6 Correct 7 ms 12032 KB Output is correct
7 Correct 7 ms 12032 KB Output is correct
8 Incorrect 7 ms 12032 KB Breaking single line is causing network to disconnect.
9 Halted 0 ms 0 KB -

Subtask #2
0 / 45.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 12088 KB Output is correct
2 Correct 6 ms 12160 KB Output is correct
3 Correct 7 ms 12032 KB Output is correct
4 Correct 7 ms 12032 KB Output is correct
5 Correct 6 ms 12032 KB Output is correct
6 Correct 7 ms 12032 KB Output is correct
7 Correct 7 ms 12032 KB Output is correct
8 Incorrect 7 ms 12032 KB Breaking single line is causing network to disconnect.
9 Halted 0 ms 0 KB -

Subtask #3
0 / 37.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 12088 KB Output is correct
2 Correct 6 ms 12160 KB Output is correct
3 Correct 7 ms 12032 KB Output is correct
4 Correct 7 ms 12032 KB Output is correct
5 Correct 6 ms 12032 KB Output is correct
6 Correct 7 ms 12032 KB Output is correct
7 Correct 7 ms 12032 KB Output is correct
8 Incorrect 7 ms 12032 KB Breaking single line is causing network to disconnect.
9 Halted 0 ms 0 KB -