875-Koko-Eating-Bananas.js

/**
 * @param {number[]} piles
 * @param {number} h
 * Time O(N * log(M)) | Space O(1)
 * @return {number}
 */
var minEatingSpeed = function (piles, h) {
    let [left, right] = [1, Math.max(...piles)];

    while (left < right) {
        const mid = (left + right) >> 1;
        const hourSpent = getHourSpent(mid, piles);

        const isTargetGreater = h < hourSpent;
        if (isTargetGreater) left = mid + 1;

        const isTargetLess = hourSpent <= h;
        if (isTargetLess) right = mid;
    }

    return right;
};

const getHourSpent = (mid, piles, hourSpent = 0) => {
    for (const pile of piles) {
        hourSpent += Math.ceil(pile / mid);
    }

    return hourSpent;
};