Submission #94394

#	Time	Username	Problem	Language	Result	Execution time	Memory
94394		gumball	Network (BOI15_net)	C++14	Compilation error	0 ms	0 KiB

net

#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
#define fi first
#define se second
using namespace std;
ll n,m,i,ta,tb,D[101010],daun,bes[101010],ROOT,j,P[101010],sudah[101010],sisa;
vector<ll> v[101010],C,w[101010];
vector<pair<pair<ll,ll> ,ll> > Z;
void dfs(ll aa,ll bb)
{
	//cout<<aa<<" "<<bb<<" "<<cc<<"\n";
	bes[aa]=0;
	if(D[aa]==1)bes[aa]=1;
	ll ii;
	for(ii=0;ii<v[aa].size();ii++)
		if(v[aa][ii]!=bb)
		{
			P[v[aa][ii]]=aa;
			dfs(v[aa][ii],aa);
			bes[aa]+=bes[v[aa][ii]];
		}
}
void dfs2(ll aa,ll bb,ll cc,ll dd)
{
	if(D[aa]==1)
	{
		kel[dd]++;
		isi[dd].pb(aa);
		Z.pb(mp(mp(cc,dd),aa));
	}
	ll ii;
	for(ii=0;ii<v[aa].size();ii++)
		if(v[aa][ii]!=bb)
			dfs2(v[aa][ii],aa,cc,dd);
}
int main()
{
	ios_base::sync_with_stdio(NULL);cin.tie(NULL);cout.tie(NULL);
	cin>>n;
	for(i=1;i<n;i++)
	{
		cin>>ta>>tb;
		v[ta].pb(tb);
		v[tb].pb(ta);
		D[ta]++;
		D[tb]++;
	}
	for(i=1;i<=n;i++)
		if(D[i]>1)
			C.pb(i);
		else
			daun++;
	//cout<<daun<<"\n";
	for(i=0;i<C.size();i++)
	{
		vector<ll> X;
		ROOT=C[i];
		//cout<<ROOT<<"\n";
		dfs(ROOT,ROOT);		
		for(j=0;j<v[ROOT].size();j++)
			X.pb(bes[v[ROOT][j]]);
		//return 0;
		sort(X.begin(),X.end());
		reverse(X.begin(),X.end());
		if(X[0]*2<=daun)
			break;
		else
			ROOT=-1;
	}
	if(ROOT==-1)while(1);
	//cout<<ROOT<<"\n";
	//return 0;
	for(i=0;i<v[ROOT].size();i++)
		dfs2(v[ROOT][i],ROOT,bes[v[ROOT][i]],i);
	cout<<(daun/2+daun%2)<<"\n";
	sort(Z.begin(),Z.end());
	if(daun%2==1)
	{
		if(P[Z[daun-1].se]!=ROOT)cout<<Z[daun-1].se<<" "<<ROOT<<"\n";
		else
		{
			for(i=1;i<=n;i++)
				if(i!=Z[daun-1].se&&P[Z[daun-1].se]!=i)
				{
					cout<<Z[daun-1].se<<" "<<i<<"\n";
					break;
				}
		}
		daun--;
		kel[Z[daun-1].fi.se]--;
		Z.pop_back();
	}
	sisa=daun/2;
	for(i=0;i<daun;i++)
	{
		vector<pair<ll,ll> > B;
		for(j=0;j<v[ROOT].size();j++)
			B.pb(mp(-kel[j],j));
		sort(B.begin(),B.end());
		cout<<isi[B[0].se].back()<<" "<<isi[B[1].se].back();
		kel[B[0].se]--;
		kel[B[1].se]--;
		isi[B[0].se].pop_back();
		isi[B[1].se].pop_back();
	}
	if(sisa)while(1);
}

Compilation message (stderr)

net.cpp: In function 'void dfs(long long int, long long int)':
net.cpp:17:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(ii=0;ii<v[aa].size();ii++)
           ~~^~~~~~~~~~~~~
net.cpp: In function 'void dfs2(long long int, long long int, long long int, long long int)':
net.cpp:29:3: error: 'kel' was not declared in this scope
   kel[dd]++;
   ^~~
net.cpp:30:3: error: 'isi' was not declared in this scope
   isi[dd].pb(aa);
   ^~~
net.cpp:30:3: note: suggested alternative: 'sisa'
   isi[dd].pb(aa);
   ^~~
   sisa
net.cpp:34:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(ii=0;ii<v[aa].size();ii++)
           ~~^~~~~~~~~~~~~
net.cpp: In function 'int main()':
net.cpp:56:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<C.size();i++)
          ~^~~~~~~~~
net.cpp:62:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(j=0;j<v[ROOT].size();j++)
           ~^~~~~~~~~~~~~~~
net.cpp:75:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<v[ROOT].size();i++)
          ~^~~~~~~~~~~~~~~
net.cpp:92:3: error: 'kel' was not declared in this scope
   kel[Z[daun-1].fi.se]--;
   ^~~
net.cpp:99:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(j=0;j<v[ROOT].size();j++)
           ~^~~~~~~~~~~~~~~
net.cpp:100:13: error: 'kel' was not declared in this scope
    B.pb(mp(-kel[j],j));
             ^~~
net.cpp:102:9: error: 'isi' was not declared in this scope
   cout<<isi[B[0].se].back()<<" "<<isi[B[1].se].back();
         ^~~
net.cpp:102:9: note: suggested alternative: 'sisa'
   cout<<isi[B[0].se].back()<<" "<<isi[B[1].se].back();
         ^~~
         sisa
net.cpp:103:3: error: 'kel' was not declared in this scope
   kel[B[0].se]--;
   ^~~