[LeetCode]Remove 9

题目描述：

LeetCode 660. Remove 9

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: 9Output: 10

Hint: n will not exceed 9 x 10^8.

题目大意：

从1开始，去掉所有包含9的整数。

得到的整数序列：1, 2, 3, 4, 5, 6, 7, 8, 10, 11, ...

给定整数n，返回序列的第n个整数。注意1是第一个数。

解题思路：

九进制

Python代码：

class Solution(object):
    def newInteger(self, n):
        """
        :type n: int
        :rtype: int
        """
        ans = ''
        while n:
            ans += str((n % 9))
            n /= 9
        return int(ans[::-1])