LeetCode in Kotlin

1696. Jump Game VI

Medium

You are given a 0-indexed integer array nums and an integer k.

You are initially standing at index 0. In one move, you can jump at most k steps forward without going outside the boundaries of the array. That is, you can jump from index i to any index in the range [i + 1, min(n - 1, i + k)] inclusive.

You want to reach the last index of the array (index n - 1). Your score is the sum of all nums[j] for each index j you visited in the array.

Return the maximum score you can get.

Example 1:

Input: nums = [1,-1,-2,4,-7,3], k = 2

Output: 7

Explanation: You can choose your jumps forming the subsequence [1,-1,4,3] (underlined above). The sum is 7.

Example 2:

Input: nums = [10,-5,-2,4,0,3], k = 3

Output: 17

Explanation: You can choose your jumps forming the subsequence [10,4,3] (underlined above). The sum is 17.

Example 3:

Input: nums = [1,-5,-20,4,-1,3,-6,-3], k = 2

Output: 0

Constraints:

Solution

import java.util.ArrayDeque
import java.util.Deque

class Solution {
    fun maxResult(nums: IntArray, k: Int): Int {
        val deque: Deque<IntArray> = ArrayDeque()
        deque.offer(intArrayOf(0, nums[0]))
        for (i in 1 until nums.size) {
            val max = deque.peek()[1]
            val next = intArrayOf(i, max + nums[i])
            while (deque.isNotEmpty() && deque.peekLast()[1] <= next[1]) {
                // PURGE FROM THE END
                deque.pollLast()
            }
            deque.offer(next)
            if (deque.peekFirst()[0] <= i - k) {
                // PURGE FROM THE HEAD
                deque.pollFirst()
            }
        }
        return deque.peekLast()[1]
    }
}