Update 239-sliding-window-maximum.js

Author: everthis

239-sliding-window-maximum.js

@@ -23,3 +23,70 @@ const maxSlidingWindow = function(nums, k) {
 
   return res
 };
+
+// another
+
+/**
+ * @param {number[]} nums
+ * @param {number} k
+ * @return {number[]}
+ */
+var maxSlidingWindow = function (nums, k) {
+  if (k === 0) return []
+  const deque = new Deque()
+  for (let i = 0; i < k - 1; i++) {
+    while (!deque.isEmpty() && deque.last().val <= nums[i]) deque.pop()
+    deque.enqueue({ val: nums[i], idx: i })
+  }
+  const result = []
+  for (let i = k - 1; i < nums.length; i++) {
+    if (!deque.isEmpty() && deque.first().idx <= i - k) deque.dequeue()
+    while (!deque.isEmpty() && deque.last().val <= nums[i]) deque.pop()
+    deque.enqueue({ val: nums[i], idx: i })
+    result.push(deque.first().val)
+  }
+  return result
+}
+
+class Deque {
+  constructor() {
+    this.head = new Node()
+    this.tail = this.head
+  }
+
+  isEmpty() {
+    return this.head.next === null
+  }
+
+  first() {
+    return this.head.next.value
+  }
+
+  last() {
+    return this.tail.value
+  }
+
+  dequeue() {
+    this.head = this.head.next
+    this.head.prev = null
+  }
+
+  enqueue(value) {
+    this.tail.next = new Node(value)
+    this.tail.next.prev = this.tail
+    this.tail = this.tail.next
+  }
+
+  pop() {
+    this.tail = this.tail.prev
+    this.tail.next = null
+  }
+}
+
+class Node {
+  constructor(value) {
+    this.value = value
+    this.next = null
+    this.prev = null
+  }
+}