LeetCode 875. Koko Eating Bananas (javascript solution)

Description:

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.

Solution:

Time Complexity : O(nlog(n))
Space Complexity: O(1)

// Binary Search approach
var minEatingSpeed = function(piles, h) {
    // Check if koko can eat all the piles in h hours at his speed
    function checkCondition(speed) {
        let time = 0
        for(const pile of piles) {
            time += Math.ceil(pile / speed);
        }

        return time <= h
    }
    // Binary search
    let left = 1, right = Math.max(...piles)
    while(left < right) {
        const mid = left + Math.floor((right-left)/2)
        if(checkCondition(mid)) {
            right = mid
        } else {
            left = mid+1
        }
    }
    return left
};