LeetCode题目:Gray Code

原题地址:https://leetcode.com/problems/gray-code/

class Solution {
public:
    vector<int> grayCode(int n) {
        vector<int> coll;
        if(n ==  || n == ) {
            coll.push_back();
            if(n)
                coll.push_back();
            return coll;
        }
        coll = (grayCode(n - ));
        int i = coll.size() - ;
        for(; i >= ; --i)
            coll.push_back(pow(2.0, n - ) + coll[i]);

        return coll;
    }
};