Sword Finger Offer Interview Question 17. Print n digits from 1 to maximum [Simple]

My solution:

First find the maximum value of n digits, for loop into the vector

class Solution {
public:
    vector<int> printNumbers(int n) {
        vector<int> res;
        if(!n)  return {};
        int max=0;
        while(n--){
            max=max*10+9;
        }   
        for(int i=1;i<=max;i++)
            res.push_back(i);
        return res;
    }
};

2. Just multiply by 10 when calculating the maximum value

class Solution {
public:
    vector<int> printNumbers(int n) {
        vector<int> res;
        if(!n)  return {};
        int max=1;
        for(int i=0;i<n;i++)    max*=10;
        for(int i=1;i<max;i++)
            res.push_back(i);
        return res;
    }
};