Submission #434955

#	Time	Username	Problem	Language	Result	Execution time	Memory
434955		Blobo2_Blobo2	Network (BOI15_net)	C++17	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);
    }
    vector<int>v;
    int cnt=0;
    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();i+=2)
            cout<<v[i]+1<<' '<<v[i+1]+1<<endl;
    }
    else{
        for(int i=0;i<v.size()-1;i+=2)
            cout<<v[i]+1<<' '<<v[i+1]+1<<endl;
        cout<<v.back()+1<<' '<<v[v.size()-2]+1<<endl;
    }
    return 0;
}

Compilation message (stderr)

net.cpp: In function 'int main()':
net.cpp:35:22: 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]
   35 |         for(int i=0;i<v.size();i+=2)
      |                     ~^~~~~~~~~
net.cpp:39:22: 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]
   39 |         for(int i=0;i<v.size()-1;i+=2)
      |                     ~^~~~~~~~~~~

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