LeetCode in Kotlin

2187. Minimum Time to Complete Trips

Medium

You are given an array time where time[i] denotes the time taken by the ith bus to complete one trip.

Each bus can make multiple trips successively; that is, the next trip can start immediately after completing the current trip. Also, each bus operates independently; that is, the trips of one bus do not influence the trips of any other bus.

You are also given an integer totalTrips, which denotes the number of trips all buses should make in total. Return the minimum time required for all buses to complete at least totalTrips trips.

Example 1:

Input: time = [1,2,3], totalTrips = 5

Output: 3

Explanation:

The total number of trips completed is 1 + 0 + 0 = 1.

The total number of trips completed is 2 + 1 + 0 = 3.

The total number of trips completed is 3 + 1 + 1 = 5.

So the minimum time needed for all buses to complete at least 5 trips is 3.

Example 2:

Input: time = [2], totalTrips = 1

Output: 2

Explanation:

There is only one bus, and it will complete its first trip at t = 2.

So the minimum time needed to complete 1 trip is 2.

Constraints:

Solution

class Solution {
    fun minimumTime(time: IntArray, totalTrips: Int): Long {
        return bs(0, Long.MAX_VALUE, time, totalTrips.toLong())
    }

    private fun bs(left: Long, right: Long, time: IntArray, totalTrips: Long): Long {
        if (left > right) {
            return Long.MAX_VALUE
        }
        val mid = left + right shr 1
        return if (isPossible(time, mid, totalTrips)) {
            Math.min(
                mid,
                bs(left, mid - 1, time, totalTrips),
            )
        } else {
            bs(mid + 1, right, time, totalTrips)
        }
    }

    private fun isPossible(time: IntArray, mid: Long, totalTrips: Long): Boolean {
        var count: Long = 0
        for (i in time) {
            count += mid / i
            if (count >= totalTrips) {
                return true
            }
        }
        return false
    }
}