leetcode 660 - Remove 9

https://leetcode.com/problems/remove-9/
https://leetcode.com/problems/remove-9/discuss/134619/Very-simple-C%2B%2B-solution-Beats-100-solutions!

Start from integer 1, remove any integer that contains 9 such as 9, 19, 29…

So now, you will have a new integer sequence: 1, 2, 3, 4, 5, 6, 7, 8, 10, 11, …

Given a positive integer n, you need to return the n-th integer after removing. Note that 1 will be the first integer.

Example 1:
Input: 9
Output: 10
Hint: n will not exceed 9 x 10^8.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
class Solution {
public:
int newInteger(int n) {

vector<int> digits;

while (n > 0) {
digits.push_back(n%9);
n /= 9;
}

int res = 0;
while (!digits.empty()) {
res *= 10;
res += digits.back();
digits.pop_back();
}
return res;
}
};