题解 | #生成格雷码#

import java.util.*;

public class GrayCode {
    public String[] getGray(int n) {
        // write code here
        // n为格雷码 由n-1位的格雷码生成
        // 比如n=3的格雷码是n=2的格雷码的首位添加0或1生成的，正序添加1之后，反序添加0

        String[]  resStrs = null;
        if (n == 1) {
            resStrs = new String[] {"0", "1"};
        } else {
            String[] strs = getGray(n - 1);
            resStrs = new String[2 * strs.length];
            for (int i = 0; i < strs.length; i++) {
                resStrs[i] = "0" + strs[i];
                resStrs[resStrs.length - 1 - i] = "1" + strs[i];
            }
        }
        return resStrs;
    }
}