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  • 【题解】【排列组合】【回溯】【Leetcode】Gray Code

    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.

    思路:

    这题其实挺简单,思路可以联想到组合问题中的回溯,改变第n位,然后再利用其余n-1位的组合重新组成n位的组合。如果在改变第n位的时候,保持其余n-1位不动,再保持第n位将其余n-1位的序列反着推回去就OK了。

    感觉程序没有写出来的必要,举个栗子反而更清楚 n = 4

    0 0 0 0
    0 0 0 1
    0 0 1 |1
    0 0 1 |0

    0 1 |1 0
    0 1 |1 1
    0 1 |0 1
    0 1 |0 0

    1 |1 0 0
    1 |1 0 1
    1 |1 1 1
    1 |1 1 0

    1 |0 1 0
    1 |0 1 1
    1 |0 0 1
    1 |0 0 0

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  • 原文地址:https://www.cnblogs.com/wei-li/p/GrayCode.html
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