用位运算符来搞⛏
2的n次方计算
http://www.nowcoder.com/questionTerminal/35a1e8b18658411388bc1672439de1d9
import java.util.*;
public class Main
{
public static void main(String [] args)
{
Scanner sc=new Scanner(System.in);
while(sc.hasNext())
{
int n=sc.nextInt();
int b=2<<n-1;
System.out.println(b);
}
}
} 
投递腾讯等公司6个岗位
