1419D1-Sage's_Birthday(easy_version).cpp

/*
	written by Pankaj Kumar.
	country:-INDIA
*/
#include <bits/stdc++.h>
using namespace std;
typedef long long ll ;
typedef vector<ll> vl;
typedef vector<bool> vb;
typedef vector<char> vc;
typedef map<ll,ll> ml;
typedef set<char>sc;
typedef set<ll> sl;
#define pan cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(0);
// define values.
#define mod 1000000007
#define phi 1.618
/* Bit-Stuff */
#define get_set_bits(a) (__builtin_popcount(a))
#define get_set_bitsll(a) ( __builtin_popcountll(a))
#define get_trail_zero(a) (__builtin_ctz(a))
#define get_lead_zero(a) (__builtin_clz(a))
#define get_parity(a) (__builtin_parity(a))
/*  Abbrevations  */
#define ff first
#define ss second
#define mp make_pair
#define line cout<<endl;
#define pb push_back
#define Endl "\n"
// loops
#define forin(arr,n) for(ll i=0;i<n;i++) cin>>arr[i];
// Some print
#define no cout<<"NO"<<endl;
#define yes cout<<"YES"<<endl;
#define cc ll test;cin>>test;while(test--)
// sort
#define all(V) (V).begin(),(V).end()
#define srt(V) sort(all(V))
#define srtGreat(V) sort(all(V),greater<ll>())
// function

ll power(ll x,ll y)
{
	ll res=1;
	// x=x%mod;
	while(y>0)
	{
		if(y%2==1)
		{
			res*=x;
			// res=res%mod;
		}
		y/=2; x*=x; // x=x%mod;
	}
	return res;
}
/* ascii value 
A=65,Z=90,a=97,z=122
*/
/*  -----------------------------------------------------------------------------------*/


ll solve()
{
	ll n;
	cin>>n;
	vl v(n,0);
	forin(v,n);
	srt(v);
	ll left=0,right=n-1;
	ll flag=0;
	vl ans;
	while(right>=left)
	{
		if(flag==0)
		{
			// cout<<v[right]<<" ";
			ans.pb(v[right]);
			right--;
			flag=1;
		}
		else
		{
			flag=0;
			ans.pb(v[left]);
			// cout<<v[left]<<" ";
			left++;
		}
	}
	ll count=0;
	if(ans.size()<3)
	{
		cout<<0<<endl;
		for(auto x:ans)
			cout<<x<<" ";
		line;
	}
	else
	{
		for(ll i=1;i<ans.size();i++)
		{
			if(ans[i]<ans[i-1]&&ans[i]<ans[i+1])
				count++;
		}
		cout<<count<<endl;
		for(auto x:ans)
			cout<<x<<" ";
		line;
	}
	return 0;
}

int main()
{
	//freopen("input.txt"a, "r", stdin);
	pan;
	solve();
	// cc
	// {
	// 	solve();
	// }
}