Submission #57859

#	Time	Username	Problem	Language	Result	Execution time	Memory
57859		IvanC	Network (BOI15_net)	C++17	0 / 100	3 ms	728 KiB

net

#include <bits/stdc++.h>
using namespace std;

typedef pair<int,int> ii;

const int MAXN = 5*1e5 + 10;

int grau[MAXN],N;
vector<int> raizes;
vector<ii> pares;

int main(){
	
	scanf("%d",&N);
	for(int i = 1;i<N;i++){
		int a,b;
		scanf("%d %d",&a,&b);
		grau[a]++;
		grau[b]++;
	}
	for(int i = 1;i<=N;i++){
		if(grau[i] == 1) raizes.push_back(i);
	}
	if(raizes.size() % 2 == 1) raizes.push_back(raizes[0]);
	while(!raizes.empty()){
		int a = raizes.back();
		raizes.pop_back();
		int b = raizes.back();
		raizes.pop_back();
		pares.push_back(ii(a,b));
	}
	printf("%d\n", (int)pares.size() );
	for(ii davez : pares){
		printf("%d %d\n",davez.first,davez.second);
	}
	
	return 0;
}

Compilation message (stderr)

net.cpp: In function 'int main()':
net.cpp:14:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&N);
  ~~~~~^~~~~~~~~
net.cpp:17:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d",&a,&b);
   ~~~~~^~~~~~~~~~~~~~~

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