题目描述

A Gray code is a list of all 2^n bit strings of length n, where any two successive strings differ in exactly one bit (i.e., their Hamming distance is one).
Your task is to create a Gray code for a given length n.

输入

The only input line has an integer n（1 ≤ n ≤ 16）.

输出

Print 2^n lines that describe the Gray code. You can print any valid solution.

样例输入 Copy

2

样例输出 Copy

00
01
11
10

#include <bits/stdc++.h>
using namespace std;
vector<string> f(int n) 
{if (n == 0) return vector<string>{"0"};else if (n == 1) return vector<string>({ "0", "1" });    else {vector<string> newcode;vector<string> code = f(n - 1);for (auto it = code.begin(); it != code.end(); it++)newcode.emplace_back("0" + *it);for (auto it = code.rbegin(); it != code.rend(); it++)newcode.emplace_back("1" + *it);return newcode;}
}
int main()
{ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);int n;cin >> n;auto ans = f(n);for (auto ele : ans) cout << ele << '\n';return 0;
}