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
解答:
每次只能改变一次二进制位。说实话看答案之前,完全不知道怎么做。
class Solution {
public:
vector<int> grayCode(int n) {
vector<int> ans(1<<n);
for (int i=0; i<(1<<n); i++)
ans[i] = i^(i>>1);
return ans;
}
};