leetcode 386. Lexicographical Numbers 字典序的排列

Given an integer n, return 1 - n in lexicographical order.

For example, given 13, return: [1,10,11,12,13,2,3,4,5,6,7,8,9].

Please optimize your algorithm to use less time and space. The input size may be as large as 5,000,000.

这道题就是做一个拓扑排序，可以使用排序来做，但是这个肯定会超时，最好使用循环来做，这是网上看的一个答案

建议和这一道题leetcode 440. K-th Smallest in Lexicographical Order 第k个字典序的数字 一起学习

代码如下：

#include <iostream>#include <vector>#include <map>#include <set>#include <queue>#include <stack>#include <string>#include <climits>#include <algorithm>#include <sstream>using namespace std;bool cmp(int a, int b){    return to_string(a) < to_string(b);}class Solution {public:    vector<int> lexicalOrder(int n)    {        vector<int> res(n,0);        int cur = 1;        for (int i = 0; i < n; i++)        {            res[i] = cur;            if (cur * 10 <= n)                cur *= 10;            else            {                if (cur >= n)                    cur /= 10;                cur += 1;                while (cur % 10 == 0)                    cur /= 10;            }        }        return res;    }    vector<int> lexicalOrderBySort(int n)     {        vector<int> res;        for (int i = 1; i <= n; i++)            res.push_back(i);        sort(res.begin(), res.end(),cmp);        return res;    }};