leetcode 爱吃香蕉的珂珂 中等

 

 

 

二分答案即可。

class Solution {
public:
    int minEatingSpeed(const vector<int>& piles, int h) {
        int l = 1, r = 0;
        for(int i = 0; i < piles.size(); ++ i) {
            r = max(piles[i], r);
        }

        int ans = -1;
        while(l <= r) {
            int mid = (l + r) >> 1;
            if(check(piles, h, mid)) {
                ans = mid;
                r = mid - 1;
            } else {
                l = mid + 1;
            }
        }
        return ans;
    }

private:
    bool check(const vector<int>& piles, const int &h, const int &mid) {
        int sum = 0;
        for(int i = 0; i < piles.size(); ++ i) {
            sum += (int) ceil(piles[i] * 1.0 / mid);
        }
        return sum <= h;
    }
};