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GrayCode.java
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GrayCode.java
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/*
Author: King, [email protected]
Date: Dec 27, 2014
Problem: Gray Code
Difficulty: Easy
Source: https://oj.leetcode.com/problems/gray-code/
Notes:
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.
Solution: Refer to http://en.wikipedia.org/wiki/Gray_code.
*/
public class Solution {
public List<Integer> grayCode(int n) {
ArrayList<Integer> res = new ArrayList<Integer>();
for (int i = 0; i < 1 << n; ++i)
res.add((int)((i >> 1) ^ i));
return res;
}
}