feat(239): 更新单调队列的代码

Author: suukii

basic/two-pointers/30.sliding-window-maximum.md

@@ -388,3 +388,56 @@ class Deque {
     }
 }
 ```
+
+单调队列 @feiker
+
+JavaScript Code
+
+```js
+var maxSlidingWindow = function (nums, k) {
+    const res = [];
+    const dequeue = new Dequeue();
+
+    // 前 k 个数据入队
+    for (let i = 0; i < k - 1; i++) {
+        dequeue.push(nums[i]);
+    }
+
+    // 滑动窗口
+    for (let i = k - 1; i < nums.length; i++) {
+        dequeue.push(nums[i]);
+        res.push(dequeue.front);
+        dequeue.shift(nums[i - k + 1]);
+    }
+    return res;
+};
+
+class Dequeue {
+    constructor() {
+        this.list = [];
+    }
+
+    get front() {
+        return this.list[0];
+    }
+
+    get tail() {
+        return this.list[this.list.length - 1];
+    }
+
+    push(val) {
+        const list = this.list;
+        // 保证数据从队头到队尾递减
+        while (this.tail < val) {
+            list.pop();
+        }
+        list.push(val);
+    }
+
+    // 队头出队
+    shift(val) {
+        // 这里的js实现shift()理论上复杂度应该是O(k), 就不去真实实现一个O(1)出队的队列了，意思到位即可
+        if (this.front === val) this.list.shift();
+    }
+}
+```