875--koko-eating-bananas.js

// 875. Koko Eating Bananas
// https://leetcode.com/problems/koko-eating-bananas/
// Medium
//Koko loves to eat bananas. There are n piles of bananas, the ith pile has piles[i] bananas. The guards have gone and will come back in h hours.
//Koko can decide her bananas-per-hour eating speed of k. Each hour, she chooses some pile of bananas and eats k bananas from that pile. If the pile has less than k bananas, she eats all of them instead and will not eat any more bananas during this hour.
//Koko likes to eat slowly but still wants to finish eating all the bananas before the guards return.
//Return the minimum integer k such that she can eat all the bananas within h hours.
//
//Example 1:
//Input: piles = [3,6,7,11], h = 8
//Output: 4
//Example 2:
//Input: piles = [30,11,23,4,20], h = 5
//Output: 30
//Example 3:
//Input: piles = [30,11,23,4,20], h = 6
//Output: 23
//
//Constraints:
//1 <= piles.length <= 104
//piles.length <= h <= 109
//1 <= piles[i] <= 109

/**
 * @param {number[]} piles
 * @param {number} h
 * @return {number}
 */
var minEatingSpeed = function (piles, h) {
    let maxPile = 0;
    for (let i = 0; i < piles.length; i++) {
        maxPile = Math.max(maxPile, piles[i]);
    }

    let left = Math.ceil(piles.reduce((a, b) => a + b, 0) / h), right = maxPile;
    while (left < right) {
        let mid = Math.floor((left + right) / 2);
        let hours = 0;
        for (let i = 0; i < piles.length; i++) {
            hours += Math.ceil(piles[i] / mid);
        }
        if (hours > h) {
            left = mid + 1;
        } else {
            right = mid;
        }
    }
    return left;
};