Two children, Lily and Ron, want to share a chocolate bar. Each of the squares has an integer on it.

Birthday cake hackerrank Subarray division

function birthday(s, d, m) {
    // Write your code here
    let result = 0;
    for(let i = 0; i < s.length; i++) {
        if (s.slice(i, i + m).reduce((r, v) => r + v, 0) === d) {
            result++;
        }
    }
    return result;
}