LeetCode 660 Remove 9 (LeetCode Weekly Contest 45)

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;
}
};