2023-03-08 Daily Challenge

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In: DailyChallenge

Today I have done leetcode's March LeetCoding Challenge with cpp.

March LeetCoding Challenge 8

Description

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 <= 104
  • piles.length <= h <= 109
  • 1 <= piles[i] <= 109

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
  int time(const vector<int> &piles, int eat) {
    int result = 0;
    for(auto pile : piles) {
      if(pile % eat) {
        result += pile / eat + 1;
      } else {
        result += pile / eat;
      }
    }
    return result;
  }
public:
  int minEatingSpeed(vector<int>& piles, int h) {
    int low = 1;
    int high = *max_element(piles.begin(), piles.end());
    while(low < high) {
      int mid = (low + high) >> 1;
      if(time(piles, mid) > h) {
        low = mid + 1;
      } else {
        high = mid;
      }
    }
    return low;
  }
};

// Accepted
// 123/123 cases passed (37 ms)
// Your runtime beats 96.29 % of cpp submissions
// Your memory usage beats 45.12 % of cpp submissions (18.9 MB)
Algorithm