Burger

http://acm.hust.edu.cn/vjudge/contest/view.action?cid=30506#problem/L

#include<map>#include<set>#include<list>#include<cmath>#include<ctime>#include<deque>#include<stack>#include<bitset>#include<cstdio>#include<vector>#include<cstdlib>#include<cstring>#include<iomanip>#include<numeric>#include<sstream>#include<utility>#include<iostream>#include<algorithm>#include<functional>using namespace std ;double n , num[ 500005 ] ; void Union(){num[ 0 ] = 0 ;for( int i = 1 ; i <= 500000 ; ++i ){num[ i ] = num[ i - 1 ] + log2( ( double ) i ) ;}}int main(){int Case ;Union() ;while( scanf( "%d" , &Case ) != EOF ){while( Case-- ){scanf( "%lf" , &n ) ;double temp = num[ ( int )n - 2 ] - 2 * num[ ( int )n / 2 - 1 ] - ( n - 2 ) ;printf( "%.4lf\n" , 1 - pow( ( double ) 2 , temp ) ) ;}}     return 0;}