LeetCode in Kotlin

2365. Task Scheduler II

Medium

You are given a 0-indexed array of positive integers tasks, representing tasks that need to be completed in order, where tasks[i] represents the type of the ith task.

You are also given a positive integer space, which represents the minimum number of days that must pass after the completion of a task before another task of the same type can be performed.

Each day, until all tasks have been completed, you must either:

Return the minimum number of days needed to complete all tasks.

Example 1:

Input: tasks = [1,2,1,2,3,1], space = 3

Output: 9

Explanation:

One way to complete all tasks in 9 days is as follows:

Day 1: Complete the 0th task.

Day 2: Complete the 1st task.

Day 3: Take a break.

Day 4: Take a break.

Day 5: Complete the 2nd task.

Day 6: Complete the 3rd task.

Day 7: Take a break.

Day 8: Complete the 4th task.

Day 9: Complete the 5th task.

It can be shown that the tasks cannot be completed in less than 9 days.

Example 2:

Input: tasks = [5,8,8,5], space = 2

Output: 6

Explanation:

One way to complete all tasks in 6 days is as follows:

Day 1: Complete the 0th task.

Day 2: Complete the 1st task.

Day 3: Take a break.

Day 4: Take a break.

Day 5: Complete the 2nd task.

Day 6: Complete the 3rd task.

It can be shown that the tasks cannot be completed in less than 6 days.

Constraints:

Solution

@Suppress("NAME_SHADOWING")
class Solution {
    fun taskSchedulerII(tasks: IntArray, space: Int): Long {
        var space = space
        var days: Long = 0
        space++
        val lastOccurence = HashMap<Int, Long>()
        for (i in tasks.indices) {
            if (lastOccurence.containsKey(tasks[i])) {
                val lastTimeOccurred = lastOccurence[tasks[i]]!!
                val daysDifference = days - lastTimeOccurred
                if (daysDifference < space) {
                    days += space - daysDifference
                }
            }
            lastOccurence[tasks[i]] = days
            days++
        }
        return days
    }
}