Leaderboard
Showing:
Handle Score
@Ibrahim Nash 6420
@blackshadows 6380
@mb1973 5646
@Quandray 5233
@akhayrutdinov 5111
@saiujwal13083 4716
@sanjay05 3762
@kirtidee18 3673
@marius_valentin_dragoi 3522
@sushant_a 3459
@verma_ji 3413
Complete Leaderboard
Number of 1's in smallest repunits
Easy Accuracy: 35.13% Submissions: 171 Points: 2

Every number whose unit’s digit is 3 has a repunit as its multiple. A repunit is a number which has only ones. It is of the form (10n – 1)/9. Example: 3 divides 111, 13 divides 111111.
A positive integer N will be given whose unit’s digit is 3. The task is to find the number of 1s in the smallest repunit which is divisible by the given number N.

Example 1:

Input: N = 3
Output: 3
Explaination: The number 111 is the first 
repunit which is divisible by 3.

Example 2:

Input: N = 13
Output: 6
Explaination: The first repunit is 111111 
which divisible by 13.

Your Task:
You do not need to read input or print anything. Your task is to complete the function repUnit() which takes N as input parameter and returns the number of 1 in the smallest repunit which is divisible by N.

Expected Time Complexity: O(N)
Expected Auxiliary Space: O(1)

Constraints:
1 ≤ N ≤ 106  

to report an issue on this page.

Editorial

We strongly recommend solving this problem on your own before viewing its editorial. Do you still want to view the editorial?

Yes

All Submissions

My Submissions:

Login to access your submissions.

Number of 1's in smallest repunits

Output Window