爱吃香蕉的珂珂
Koko Eating Bananas
题目详情
问题：爱吃香蕉的珂珂
考察：数组、二分查找
来源：Citadel
链接：https://www.jointaro.com/interviews/questions/koko-eating-bananas/
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 <= 104piles.length <= h <= 1091 <= piles[i] <= 109
解析
思路：答案是吃香蕉速度，在 1 到最大堆大小之间二分。给定速度 k，可以计算总小时数 sum(ceil(pile/k))，若不超过 h 则速度可行并尝试更小。
复杂度：时间 O(n log M)，空间 O(1)。