Submission #434961

#	Time	Username	Problem	Language	Result	Execution time	Memory
434961		Blobo2_Blobo2	Network (BOI15_net)	C++14	0 / 100	1 ms	204 KiB

net

/*
Editor: Abdelrahman Hossam
Nickname: Blobo2_Blobo2
IOI next year isA :)
*/
//#pragma GCC optimize ("O3")
//#pragma GCC optimize ("unroll-loops")
#include<bits/stdc++.h>
using namespace std;
#define int long long
#define endl "\n"
#define all(v)  v.begin(),v.end()
#define gen(arr,n,nxt)  generate(arr,arr+n,nxt)
#define Blobo2_el_gamded_gedan_elly_3ayz_yro7_IOI_w_3ayz_yakol_jilaty ios_base::sync_with_stdio(false);cin.tie(0);

const int mo=1e9+7;
int nxt(){int x;cin>>x;return x;}

signed main(){
    Blobo2_el_gamded_gedan_elly_3ayz_yro7_IOI_w_3ayz_yakol_jilaty
    int n=nxt();
    vector<int>adj[n];
    for(int i=0;i<n-1;i++){
        int x=nxt()-1,y=nxt()-1;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    int cnt=0;
    vector<int>v;
    for(int i=0;i<n;i++){
        if(adj[i].size()==1){
            cnt++;
            v.push_back(i);
        }
    }
    cout<<(cnt+1)/2<<endl;
    if(cnt%2==0){
        for(int i=0;i<v.size()/2;i++)
            cout<<v[i]+1<<' '<<v[i+(cnt/2)]+1<<endl;
    }
    else{
        for(int i=0;i<v.size()/2;i++)
            cout<<v[i]+1<<' '<<v[i+(cnt/2+1)]+1<<endl;
        cout<<v[cnt/2]+1<<' ';
        int p = adj[v.back()][0];
        for(int i=0;i<n;i++){
            if(i!=p&&i!=v.back()){
                cout<<i+1<<endl;
                break;
            }
        }
    }
    return 0;
}

Compilation message (stderr)

net.cpp: In function 'int main()':
net.cpp:38:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |         for(int i=0;i<v.size()/2;i++)
      |                     ~^~~~~~~~~~~
net.cpp:42:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |         for(int i=0;i<v.size()/2;i++)
      |                     ~^~~~~~~~~~~

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