oj.uz

Submission #640189

# Submission time Handle Problem Language Result Execution time Memory
640189 2022-09-13T22:09:23 Z sondos225 Network (BOI15_net) C++17
0 / 100
 2 ms 4192 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T>using ordered_set = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;//find_by_order(ind);//order_of_key()
#define int long long
#define fast ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL);
#define pb emplace_back
#define pf emplace_front
#define yes "YES"
#define no "NO"
#define bigg INT_MAX
#define mp make_pair
#define mt make_tuple
#define debug(x) cout<<(#x)<<" = " <<x<<endl;
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define sz size()
#define nn '\n'
#define mms(x,y) memset(x,y,sizeof(x))
#define forr(i,j,n) for (int i=j; i<n; i++)
#define forn(i,j,n) for (int i=j; i>n; i--)
#define cinn(x,y) for(int i=0; i<y; i++) cin>>x[i];
#define fi first
#define se second
#define la "LA"
#define pii pair<int,int>
// to use cmd ctrl+shift+c then g++ name.cpp -o name2.exe then name2 then input
//ctrl+shift+p to open search
//shift+alt+a stack comment2
///power function works in log2b
// int pwr(int a, int b)
// {
//   int po = 1;
//   while ( b )
//   {
//          if ( b & 1 )
//          {
//            po = po * a;
//            --b;
//          }
//          a = a*a;
//          b = b/2;
//   }
//   return po;
// }
int len[500001];
bool cmp (int a,int b)
{
    return len[a]<len[b];
}
signed main()
{
    fast
    //  #ifndef LOCAL
    //  freopen("in.txt","r",stdin);
    //  freopen("out.txt","w",stdout);
    //  #endif
    int n;
    cin>>n;
    vector <int> a[n+1];
    forr(i,0,n-1)
    {
        int x,y;
        cin>>x >>y;
        a[x].pb(y);
        a[y].pb(x);
    }
    vector <int> leaf;
    forr(i,1,n+1)
    {
        if (a[i].sz==1)
        {
            leaf.pb(i);
        }
    }
    
    mms(len,-1);
    queue <int> q;
    q.push(leaf[0]);
    len[leaf[0]]=0;
    while(!q.empty())
    {
        int w=q.front();
        q.pop();
        forr(i,0,a[w].sz)
        {
            if (len[a[w][i]]==-1)
            {
                len[a[w][i]]=len[w]+1;
                q.push(a[w][i]);
            }
        }
    }
    int cnt=(leaf.sz/2)+(leaf.sz%2);
    cout<<cnt<<nn;
    sort(all(leaf),cmp);
    cnt=leaf.sz;
    // cout<<leaf.sz<<endl<<endl;
    int i=0, j=cnt-1;
    while(cnt>0)
    {
        // cout<<yes<<cnt<<endl;
        if (cnt==1)
        {
            cout<<leaf[i]<<' '<<leaf[0]<<nn;
        }
        else
        {
            cout<<leaf[i]<<' '<<leaf[j]<<nn;
            i++;
            j--;
        }
        cnt-=2;
    }
    return 0;
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:22:36: 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]
   22 | #define forr(i,j,n) for (int i=j; i<n; i++)
      |                                    ^
net.cpp:87:9: note: in expansion of macro 'forr'
   87 |         forr(i,0,a[w].sz)
      |         ^~~~

Subtask #1
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4180 KB Output is correct
2 Correct 2 ms 4180 KB Output is correct
3 Correct 2 ms 4176 KB Output is correct
4 Correct 2 ms 4180 KB Output is correct
5 Correct 2 ms 4164 KB Output is correct
6 Correct 2 ms 4168 KB Output is correct
7 Correct 2 ms 4180 KB Output is correct
8 Correct 2 ms 4180 KB Output is correct
9 Correct 2 ms 4180 KB Output is correct
10 Correct 2 ms 4180 KB Output is correct
11 Correct 2 ms 4180 KB Output is correct
12 Correct 2 ms 4180 KB Output is correct
13 Correct 2 ms 4172 KB Output is correct
14 Correct 2 ms 4192 KB Output is correct
15 Correct 2 ms 4180 KB Output is correct
16 Correct 2 ms 4180 KB Output is correct
17 Correct 2 ms 4180 KB Output is correct
18 Incorrect 2 ms 4172 KB Breaking single line is causing network to disconnect.
19 Halted 0 ms 0 KB -

Subtask #2
0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4180 KB Output is correct
2 Correct 2 ms 4180 KB Output is correct
3 Correct 2 ms 4176 KB Output is correct
4 Correct 2 ms 4180 KB Output is correct
5 Correct 2 ms 4164 KB Output is correct
6 Correct 2 ms 4168 KB Output is correct
7 Correct 2 ms 4180 KB Output is correct
8 Correct 2 ms 4180 KB Output is correct
9 Correct 2 ms 4180 KB Output is correct
10 Correct 2 ms 4180 KB Output is correct
11 Correct 2 ms 4180 KB Output is correct
12 Correct 2 ms 4180 KB Output is correct
13 Correct 2 ms 4172 KB Output is correct
14 Correct 2 ms 4192 KB Output is correct
15 Correct 2 ms 4180 KB Output is correct
16 Correct 2 ms 4180 KB Output is correct
17 Correct 2 ms 4180 KB Output is correct
18 Incorrect 2 ms 4172 KB Breaking single line is causing network to disconnect.
19 Halted 0 ms 0 KB -

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4180 KB Output is correct
2 Correct 2 ms 4180 KB Output is correct
3 Correct 2 ms 4176 KB Output is correct
4 Correct 2 ms 4180 KB Output is correct
5 Correct 2 ms 4164 KB Output is correct
6 Correct 2 ms 4168 KB Output is correct
7 Correct 2 ms 4180 KB Output is correct
8 Correct 2 ms 4180 KB Output is correct
9 Correct 2 ms 4180 KB Output is correct
10 Correct 2 ms 4180 KB Output is correct
11 Correct 2 ms 4180 KB Output is correct
12 Correct 2 ms 4180 KB Output is correct
13 Correct 2 ms 4172 KB Output is correct
14 Correct 2 ms 4192 KB Output is correct
15 Correct 2 ms 4180 KB Output is correct
16 Correct 2 ms 4180 KB Output is correct
17 Correct 2 ms 4180 KB Output is correct
18 Incorrect 2 ms 4172 KB Breaking single line is causing network to disconnect.
19 Halted 0 ms 0 KB -