Hackerrank - Repeated String Solution

Lilah has a string, , of lowercase English letters that she repeated infinitely many times.

Given an integer, , find and print the number of letter a's in the first  letters of Lilah's infinite string.

For example, if the string  and , the substring we consider is , the first  characters of her infinite string. There are  occurrences of a in the substring.

Function Description

Complete the repeatedString function in the editor below. It should return an integer representing the number of occurrences of a in the prefix of length  in the infinitely repeating string.

repeatedString has the following parameter(s):

• s: a string to repeat
• n: the number of characters to consider

Input Format

The first line contains a single string, .
The second line contains an integer, .

Constraints

• For  of the test cases, .

Output Format

Print a single integer denoting the number of letter a's in the first  letters of the infinite string created by repeating  infinitely many times.

Sample Input 0

aba
10

Sample Output 0

7

Explanation 0
The first  letters of the infinite string are abaabaabaa. Because there are  a's, we print  on a new line.

Sample Input 1

a
1000000000000

Sample Output 1

1000000000000

Explanation 1
Because all of the first  letters of the infinite string are a, we print  on a new line.

Solution in Python

def repeatedString(s, n):
    x,y = divmod(n,len(s))
    return s[:y].count("a")*(x+1) + s[y:].count("a")*x
s = input()
n = int(input())
print(repeatedString(s, n))