Gray Code leetcode java
题目:
The gray code is a binary numeral system where two successive values differ in only one bit.
Given a non-negative integer n representing the total number of bits in the code, print the sequence of gray code. A gray code sequence must begin with 0.
For example, given n = 2, return [0,1,3,2]
. Its gray code sequence is:
00 - 0
01 - 1
11 - 3
10 - 2
Note:
For a given n, a gray code sequence is not uniquely defined.
For example, [0,2,3,1]
is also a valid gray code sequence according to the above definition.
For now, the judge is able to judge based on one instance of gray code sequence. Sorry about that.
题解:
这道题是要考我知不知道格雷码么。。反正我自己单看找不出规律。。。
可以看到n位的格雷码由两部分构成,一部分是n-1位格雷码,再加上 1<<(n-1)和n-1位格雷码的逆序(整个格雷码逆序0132变成2310这种)的和。
1位格雷码有两个码字
(n+1)位格雷码中的前2^n个码字等于n位格雷码的码字,按顺序书写,加前缀0
(n+1)位格雷码中的后2^n个码字等于n位格雷码的码字,按逆序书写,加前缀1。
由于是二进制,在最高位加0跟原来的数本质没有改变,所以取得上一位算出的格雷码结果,再加上逆序添1的方法就是当前这位格雷码的结果了。
n = 0时,[0]
n = 1时,[0,1]
n = 2时,[00,01,11,10]
n = 3时,[000,001,011,010,110,111,101,100]
当n=1时,0,1
当n=2时,原来的list 0,1不变,只是前面形式上加了个0变成00,01。然后加数是1<<1为10,依次:10+1=11 10+0=10。结果为:00 01 11 10
当n=3时,原来的list 00,01,11, 10(倒序为:10,11,01,00)。加数1<<2为100。倒序相加为:100+10=110, 100+11=,100+01=, 100+00= 100。
最终结果为000 001 011 010 110 111 101 100
代码如下:
1 public ArrayList<Integer> grayCode(int n) {
2 if(n==0) {
3 ArrayList<Integer> result = new ArrayList<Integer>();
4 result.add(0);
5 return result;
6 }
7
8 ArrayList<Integer> result = grayCode(n-1);
9 int addNumber = 1 << (n-1);
int originalsize=result.size();
for(int i=originalsize-1;i>=0;i--) {
result.add(addNumber + result.get(i));
}
return result;
}
Gray Code leetcode java的更多相关文章
- 89. Gray Code - LeetCode
Question 89. Gray Code Solution 思路: n = 0 0 n = 1 0 1 n = 2 00 01 10 11 n = 3 000 001 010 011 100 10 ...
- Gray Code -- LeetCode
原标题链接: http://oj.leetcode.com/problems/gray-code/ 这道题要求求出n位的格雷码相应的二进制数,主要在于找到一种格雷码的递增方法(格雷码并非唯一的,能够 ...
- Java for LeetCode 089 Gray Code
The gray code is a binary numeral system where two successive values differ in only one bit. Given a ...
- [LeetCode] 89. Gray Code 格雷码
The gray code is a binary numeral system where two successive values differ in only one bit. Given a ...
- [LeetCode] Gray Code 格雷码
The gray code is a binary numeral system where two successive values differ in only one bit. Given a ...
- [LeetCode]题解(python):089 Gray Code
题目来源 https://leetcode.com/problems/gray-code/ The gray code is a binary numeral system where two suc ...
- 【一天一道LeetCode】#89. Gray Code
一天一道LeetCode 本系列文章已全部上传至我的github,地址:ZeeCoder's Github 欢迎大家关注我的新浪微博,我的新浪微博 欢迎转载,转载请注明出处 (一)题目 The gra ...
- [leetcode]Gray Code @ Python
原题地址:https://oj.leetcode.com/problems/gray-code/ 题意: The gray code is a binary numeral system where ...
- LeetCode: Gray Code 解题报告
Gray CodeThe gray code is a binary numeral system where two successive values differ in only one bit ...
随机推荐
- windows系统,联系人文件。个性化。
韩梦飞沙 韩亚飞 313134555@qq.com yue31313 han_meng_fei_sha ======= 文件下载链接:
- BZOJ.1396.识别子串(后缀自动机/后缀数组 线段树)
题目链接 SAM:能成为识别子串的只有那些|right|=1的节点代表的串. 设这个节点对应原串的右端点为r[i],则如果|right[i]|=1,即\(s[\ [r_i-len_i+1,r_i-le ...
- Codeforces Round #515 (Div. 3)
Codeforces Round #515 (Div. 3) #include<bits/stdc++.h> #include<iostream> #include<cs ...
- android流量统计
研究过一段时间的android流量统计发个自己的总结帖 1 android有一个TrafficStats类可以直接获取 总接受流量TrafficStats.getTotalRxBytes(), 总发送 ...
- Programming Internal Flash Over the Serial Wire Debug <SWD> Interface -- EFM32
1 Debug Interface Overview 1.1 Serial Wire Debug Serial Wire Debug (SWD) is a two-wire protocol for ...
- gitblit.cmd运行自动关闭
前几天运行gitblit.cmd一直正常,今天运行gitblit.cmd,几秒钟后命令行窗口就自动关闭了,导致无法启动gitblit服务器,查看日志如下: 刚开始以为是防火墙问题,在防火墙中添加了程序 ...
- poll() can't detect event when socket is closed locally?
from https://stackoverflow.com/questions/5039608/poll-cant-detect-event-when-socket-is-closed-locall ...
- The main reborn ASP.NET MVC4.0: using CheckBoxListHelper and RadioBoxListHelper
The new Helpers folder in the project, to create the CheckBoxListHelper and RadioBoxListHelper class ...
- NSArray进行汉字排序
由于NSArray并不直接支持对汉字的排序,这就要通过将汉字转换成拼音完毕按A~Z的排序,这看起来是个头疼的问题.由于牵扯到汉字转为拼音,kmyhy给出一个较易实现的方法,获取汉字的首字的首字母,如将 ...
- 再议ASP.NET MVC中CheckBoxList的验证
在ASP.NET MVC 4中谈到CheckBoxList,经常是与CheckBoxList的显示以及验证有关.我在"MVC扩展生成CheckBoxList并水平排列"中通过扩展H ...