Submission #25733

#	Time	Username	Problem	Language	Result	Execution time	Memory
25733		nibnalin	Network (BOI15_net)	C++14	0 / 100	0 ms	3972 KiB

net

#include <iostream>
#include <cstdio>
#include <vector>
using namespace std;

const int maxn = int(5e5)+5;

int deg[maxn];

int main(void)
{
	int n, u, v;
	scanf("%d", &n);
	for(int i = 1;i < n;i++)
	{
		scanf("%d%d", &u, &v);
		u--, v--;
		deg[u]++, deg[v]++;
	}

	vector<int> leafs;
	for(int i = 0;i < n;i++)
	{
		if(deg[i] == 1)
		{
			leafs.push_back(i);
		}
	}

	printf("%d\n", int(leafs.size())/2+int(leafs.size())%2);
	for(int i = 0;i < int(leafs.size())-1;i += 2)
	{
		printf("%d %d\n", leafs[i]+1, leafs[i+1]+1);
	}

	if(int(leafs.size()%2)) printf("%d %d\n", leafs[int(leafs.size())-2]+1, leafs[int(leafs.size())-1]+1);
}

Compilation message (stderr)

net.cpp: In function 'int main()':
net.cpp:13:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
                 ^
net.cpp:16:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &u, &v);
                        ^

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