Function addRightFrequency

javascript/0567-permutation-in-string.js:47–54

(s, right, frequencyMap)

const getCode = (char) => char.charCodeAt(0) - 'a'.charCodeAt(0);

const addRightFrequency = (s, right, frequencyMap) => {
    const char = s[right];
    const index = getCode(char);

    frequencyMap[index]++;

    return frequencyMap[index];
};

const subtractLeftFrequency = (s, left, frequencyMap) => {
    const char = s[left];