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.
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public class Solution { /**We start from 00...0 and 000...1. Changing i-th bit for each for them is same as to * add pow(2, i) to them. * * @param n --Integer, the length of the binary string * @return List<Integer> --all possible * @author Averill Zheng * @version 2014-06-05 * @since JDK 1.7 */ public
List<Integer> grayCode(int
n) { List<Integer> result = new
ArrayList<Integer>(); result.add(0); if(n > 0){ result.add(1); int
length = 2; for(int
i = 1; i < n; ++i){ for(int
j = length - 1; j > -1; --j) result.add(result.get(j) + (int)Math.pow(2, i)); length *= 2; } } return
result; }} |
leetcode--Gray Code,布布扣,bubuko.com
原文地址：http://www.cnblogs.com/averillzheng/p/3773800.html
