875. Koko Eating Bananas

class Solution {
    public int minEatingSpeed(int[] piles, int h) {
        int left = 1, right = 1000000000; // 注意速度不能为 0
        while (left < right) {
            int mid = (left + right) >>> 1;
            if (canEat(mid, piles, h)) {
                right = mid;
            } else {
                left = mid + 1;
            }
        }

        return left;
    }

    private boolean canEat(int speed, int[] piles, int h) {
        int hour = 0;
        for (int pile : piles) {
            hour += pile / speed + (pile % speed != 0 ? 1 : 0);
            if (hour > h) {
                return false;
            }
        }

        return true;
    }
}

References

875. Koko Eating Bananas
剑指 Offer II 073. 狒狒吃香蕉