gray code 格雷码 递归

格雷码

the n-1 bit code, with 0 prepended to each word, followd by the n-1 bit code in reverse order, 

with 1 prepended to each word.

public class GrayCode{
    public static void gray(int n, String prefix)
    {
        if(n == 0)
            System.out.println(prefix);
        else
        {
            gray(n-1,prefix + "0");
            yarg(n-1,prefix + "1");
        }
    }
    public static void yarg(int n, String prefix)
    {
        if(n == 0)
            System.out.println(prefix);
        else
        {
            gray(n-1,prefix + "1");
            yarg(n-1,prefix + "0");
        }        
    }
    public static void main(String[] args)
    {
        int N = Integer.parseInt(args[0]);
        gray(N, "");
    }
}

运行结果

> java GrayCode 3
000
001
011
010
110
111
101
100