Package g1801_1900.s1870_minimum_speed_to_arrive_on_time

Class Solution

  • public class Solution
extends Object
    1870 - Minimum Speed to Arrive on Time\. Medium You are given a floating-point number `hour`, representing the amount of time you have to reach the office. To commute to the office, you must take `n` trains in sequential order. You are also given an integer array `dist` of length `n`, where `dist[i]` describes the distance (in kilometers) of the ith train ride. Each train can only depart at an integer hour, so you may need to wait in between each train ride. * For example, if the 1st train ride takes `1.5` hours, you must wait for an additional `0.5` hours before you can depart on the 2nd train ride at the 2 hour mark. Return _the **minimum positive integer** speed **(in kilometers per hour)** that all the trains must travel at for you to reach the office on time, or_ `-1` _if it is impossible to be on time_. Tests are generated such that the answer will not exceed 107 and `hour` will have **at most two digits after the decimal point**. **Example 1:** **Input:** dist = [1,3,2], hour = 6 **Output:** 1 **Explanation:** At speed 1: - The first train ride takes 1/1 = 1 hour. - Since we are already at an integer hour, we depart immediately at the 1 hour mark. The second train takes 3/1 = 3 hours. - Since we are already at an integer hour, we depart immediately at the 4 hour mark. The third train takes 2/1 = 2 hours. - You will arrive at exactly the 6 hour mark. **Example 2:** **Input:** dist = [1,3,2], hour = 2.7 **Output:** 3 **Explanation:** At speed 3: - The first train ride takes 1/3 = 0.33333 hours. - Since we are not at an integer hour, we wait until the 1 hour mark to depart. The second train ride takes 3/3 = 1 hour. - Since we are already at an integer hour, we depart immediately at the 2 hour mark. The third train takes 2/3 = 0.66667 hours. - You will arrive at the 2.66667 hour mark. **Example 3:** **Input:** dist = [1,3,2], hour = 1.9 **Output:** -1 **Explanation:** It is impossible because the earliest the third train can depart is at the 2 hour mark. **Constraints:** * `n == dist.length` * 1 <= n <= 105 * 1 <= dist[i] <= 105 * 1 <= hour <= 109 * There will be at most two digits after the decimal point in `hour`.

    • Constructor Detail

      • Solution

        public Solution()

    • Method Detail

      • minSpeedOnTime

        public int minSpeedOnTime​(int[] dist,
                          double hour)