04
08/2015
[LeetCode] Gray Code
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.
解题思路：
格雷码，相邻两个二进制之间只有一位不同。n位二进制的格雷码的数目是2^n个，且第i个格雷码为(i>>1)^i。估计题目有点问题，当n为0时，应该返回{}，但是这里要求返回{0}
class Solution {
public:
vector<int> grayCode(int n) {
vector<int> result;
if(n<0){
return result;
}
int num = 1<<n;
for(int i=0; i<num; i++){
result.push_back((i>>1)^i);
}
return result;
}
};转载请注明：康瑞部落 » [LeetCode] Gray Code
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