leetcode_gym/_problems/koko_eating_bananas.md

layout, title, last_solved, category, leetcode_url, status

layout	title	last_solved	category	leetcode_url	status
page	Koko Eating Bananas		binary search	https://leetcode.com/problems/koko-eating-bananas	Attempted

Problem

Koko loves to eat bananas.  There are N piles of bananas, the i-th 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 won't eat any more bananas during this hour.

Koko likes to eat slowly, but still wants to finish eating all the bananas before the guards come back.

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

Solution

Itiotion from this video

Code from powerful binary search template

{% highlight python %}

def minEatingSpeed(self, piles: List[int], H: int) -> int:
    
    
    def feasible(speed):  # mid is like "eating speed"
        
        total = 0
        for pile in piles:
            div = pile // speed
            if pile % speed != 0:
                div +=1
            total += div
        
        return total <= H
        
    
    left, right = 1, max(piles)
    
    while left < right:
        
        mid = (left + right) // 2   # mid is like "eating speed"
        
        if feasible(mid):
            right = mid     # it's feasible but we want to find the smallest k, so ignore right side
        else:
            left = mid + 1
    
    return left

{% endhighlight %}

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{% highlight python %}

{% endhighlight %}