牛客 QQ1 生成格雷码

概述

https://www.nowcoder.com/practice/50959b5325c94079a391538c04267e15

递归法

class GrayCode {
public:
    vector<string> getGray(int n) {
        // write code here
        if (n == 1) return {"0", "1"};
        auto n_1 = getGray(n-1);
        vector<string> ans;
        for (auto s : n_1) {
            ans.push_back("0"+s);
        }
        reverse(n_1.begin(), n_1.end());
        for (auto s : n_1) {
            ans.push_back("1"+s);
        }
        return ans;
    }
};