LeetCode-in-All
239. Sliding Window Maximum
Hard
You are given an array of integers nums, there is a sliding window of size k which is moving from the very left of the array to the very right. You can only see the k numbers in the window. Each time the sliding window moves right by one position.
Return the max sliding window.
Example 1:
Input: nums = [1,3,-1,-3,5,3,6,7], k = 3
Output: [3,3,5,5,6,7]
Explanation:
Window position Max
--------------- -----
[1 3 -1] -3 5 3 6 7 3
1 [3 -1 -3] 5 3 6 7 3
1 3 [-1 -3 5] 3 6 7 5
1 3 -1 [-3 5 3] 6 7 5
1 3 -1 -3 [5 3 6] 7 6
1 3 -1 -3 5 [3 6 7] 7
Example 2:
Input: nums = [1], k = 1
Output: [1]
Example 3:
Input: nums = [1,-1], k = 1
Output: [1,-1]
Example 4:
Input: nums = [9,11], k = 2
Output: [11]
Example 5:
Input: nums = [4,-2], k = 2
Output: [4]
Constraints:
1 <= nums.length <= 105-104 <= nums[i] <= 1041 <= k <= nums.length
Solution
import java.util.LinkedList
class Solution {
fun maxSlidingWindow(nums: IntArray, k: Int): IntArray {
val n = nums.size
val res = IntArray(n - k + 1)
var x = 0
val dq = LinkedList<Int>()
var i = 0
var j = 0
while (j < nums.size) {
while (dq.isNotEmpty() && dq.peekLast() < nums[j]) {
dq.pollLast()
}
dq.addLast(nums[j])
if (j - i + 1 == k) {
res[x] = dq.peekFirst()
++x
if (dq.peekFirst() == nums[i]) {
dq.pollFirst()
}
++i
}
++j
}
return res
}
}