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.

直接把n从十进制转换成九进制，但是要用int来表示这个九进制的数。

class Solution {
public:
    int newInteger(int n) 
    {
        stack<int> s;
        int cnt = 0, ret = 0;
        while (n > 0)
        {
            int tmp = n % 9;
            s.push(tmp);
            ++cnt;
            n = n / 9;
        }
        int mul = 1;
        while (--cnt) mul *= 10;
        while (!s.empty())
        {
            int tmp = s.top();
            s.pop();
            ret = ret + tmp * mul;
            mul /= 10;
        }
        return ret;
    }
};