gistfile1.txt

// eddy1021
#include <bits/stdc++.h>
using namespace std;
typedef double D;
typedef long long ll;
typedef pair<int,int> PII;
#define mod9 1000000009ll
#define mod7 1000000007ll
#define INF  1023456789ll
#define INF16 10000000000000000ll
#define FI first
#define SE second
#define PB push_back
#define MP make_pair
#define MT make_tuple
#define eps 1e-9
#define SZ(x) (int)(x).size()
#define ALL(x) (x).begin(), (x).end()
ll getint(){
  ll _x=0,_tmp=1; char _tc=getchar();    
  while( (_tc<'0'||_tc>'9')&&_tc!='-' ) _tc=getchar();
  if( _tc == '-' ) _tc=getchar() , _tmp = -1;
  while(_tc>='0'&&_tc<='9') _x*=10,_x+=(_tc-'0'),_tc=getchar();
  return _x*_tmp;
}
ll mypow( ll _a , ll _x , ll _mod ){
  if( _x == 0 ) return 1ll;
  ll _tmp = mypow( _a , _x / 2 , _mod );
  _tmp = ( _tmp * _tmp ) % _mod;
  if( _x & 1 ) _tmp = ( _tmp * _a ) % _mod;
  return _tmp;
}
bool equal( D _x ,  D _y ){
  return _x > _y - eps && _x < _y + eps;
}
int __ = 1 , cs;
/*********default*********/
#define N 514514
int n , a[ N ] , tk;
void build(){

}
void init(){
  n = getint(); tk = ( n - 2 ) / 2;
  for( int i = 0 ; i < n ; i ++ )
    a[ i ] = getint();
  sort( a , a + n );
}
bool okay( int dlt ){
  int pre = a[ 0 ] , bn = 0;
  for( int i = 1 ; i < n ; i ++ )
    if( a[ i ] - pre < dlt ) bn ++;
    else pre = a[ i ];
  return bn <= tk;
}
void solve(){
  int l = 1 , r = a[ n - 1 ] - a[ 0 ], mid, ans = 1;
  while( l <= r ){
    mid = ( l + r ) >> 1;
    if( okay( mid ) ) ans = mid, l = mid + 1;
    else r = mid - 1;
  }
  printf( "%d\n" , ans );
}
int main(){
  build();
  //__ = getint();
  while( __ -- ){
    init();
    solve();
  }
}