Smallest Integer Divisible by K - LeetCode

Given a positive integer k, you need to find the length of the smallest positive integer n such that n is divisible by k, and n only contains the digit 1. Return __the length of __n. If there is no such n, return -1. Note: n may not fit in a 64-bit signed integer.

Example 1: Input: k = 1 Output: 1 Explanation: The smallest answer is n = 1, which has length 1. Example 2: Input: k = 2 Output: -1 Explanation: There is no such positive integer n divisible by 2. Example 3: Input: k = 3 Output: 3 Explanation: The smallest answer is n = 111, which has length 3.

Constraints:

```
1 <= k <= 105
```

- code

```
class Solution:
def smallestRepunitDivByK(self, k: int) -> int:
n = 1
for length in range(1, k+1):
if n % k == 0: return length
n = n * 10 + 1
n = n % k
return -1
```