Repeated String

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

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

For example, if the string s = ‘abcac’ and n = 10, the substring we consider is abcacabcac, the first 10 characters of her infinite string. There are 4 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 n 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, s. The second line contains an integer, n.

Constraints

• 
• 
• For 25% of the test cases, .

Output Format

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

Sample Input 0

1
2

aba
10

Sample Output 0

1

7

Explanation 0

The first n = 10 letters of the infinite string are abaabaabaa. Because there are 7 a’s, we print 7 on a new line.

Sample Input 1

1
2

a
1000000000000

Sample Output 1

1

1000000000000

Explanation 1

Because all of the first n = 1000000000000 letters of the infinite string are a, we print 1000000000000 on a new line.

Solution

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function repeatedString(s, n) {
    let strings = [...s];
    let multiNum = Math.floor(n / strings.length);
    let restNum = n % strings.length;
    
    let setNum = strings.reduce((target, s, index) => {
        s === 'a' && target['multi']++;
        s === 'a' && index < restNum && target['rest']++;

        return target;
    }, { multi: 0, rest: 0 });

    return multiNum * setNum['multi'] + setNum['rest'];
}