Function addRightFrequency

javascript/0076-minimum-window-substring.js:51–62

(s, right, frequencyMap, matched)

};

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

    if (frequencyMap.has(char)) {
        frequencyMap.set(char, frequencyMap.get(char) - 1);

        const isInWindow = 0 <= frequencyMap.get(char);
        if (isInWindow) matched++;
    }

    return matched;
};

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