Submission #42651

#	Time	Username	Problem	Language	Result	Execution time	Memory
42651		XmtosX	Network (BOI15_net)	C++14	0 / 100	11 ms	12396 KiB

net

#include <bits/stdc++.h>
using namespace std;
int n,last;
queue <int> q;
vector <int> v[500005];
int main()
{
    scanf("%d",&n);
    for (int i=0;i<n-1;i++)
    {
        int a,b;
        scanf("%d%d",&a,&b);
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for (int i=1;i<=n;i++)
    {
        if (v[i].size()==1)
            q.push(i);
    }
    printf("%d\n",q.size()/2+(q.size())%2);
    while (q.size()>1)
    {
        last=q.front();
        printf("%d ",q.front());
        q.pop();
        printf("%d\n",q.front());
        q.pop();
    }
    if (!q.empty())
        printf("%d %d\n",q.front(),last);
    return 0;
}

Compilation message (stderr)

net.cpp: In function 'int main()':
net.cpp:21:42: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::queue<int>::size_type {aka long unsigned int}' [-Wformat=]
     printf("%d\n",q.size()/2+(q.size())%2);
                                          ^
net.cpp:8:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
                   ^
net.cpp:12:28: 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