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api/middleware/schedule/infrastructure/PriorityQueue.js

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+/**
+ * 优先级队列实现（使用最小堆）
+ * 优先级高的任务（priority值大）会优先出队
+ */
+class PriorityQueue {
+    constructor() {
+        this.heap = [];
+    }
+
+    /**
+     * 获取父节点索引
+     */
+    parent(index) {
+        return Math.floor((index - 1) / 2);
+    }
+
+    /**
+     * 获取左子节点索引
+     */
+    leftChild(index) {
+        return 2 * index + 1;
+    }
+
+    /**
+     * 获取右子节点索引
+     */
+    rightChild(index) {
+        return 2 * index + 2;
+    }
+
+    /**
+     * 交换两个节点
+     */
+    swap(i, j) {
+        [this.heap[i], this.heap[j]] = [this.heap[j], this.heap[i]];
+    }
+
+    /**
+     * 上浮操作（插入时使用）
+     */
+    bubbleUp(index) {
+        if (index === 0) return;
+
+        const parentIndex = this.parent(index);
+        const current = this.heap[index];
+        const parent = this.heap[parentIndex];
+
+        // 优先级高的在前（priority值大），如果优先级相同，创建时间早的在前
+        if (
+            current.priority > parent.priority ||
+            (current.priority === parent.priority && current.createdAt < parent.createdAt)
+        ) {
+            this.swap(index, parentIndex);
+            this.bubbleUp(parentIndex);
+        }
+    }
+
+    /**
+     * 下沉操作（删除时使用）
+     */
+    bubbleDown(index) {
+        const leftIndex = this.leftChild(index);
+        const rightIndex = this.rightChild(index);
+        let largest = index;
+
+        const current = this.heap[index];
+
+        // 比较左子节点
+        if (leftIndex < this.heap.length) {
+            const left = this.heap[leftIndex];
+            if (
+                left.priority > current.priority ||
+                (left.priority === current.priority && left.createdAt < current.createdAt)
+            ) {
+                largest = leftIndex;
+            }
+        }
+
+        // 比较右子节点
+        if (rightIndex < this.heap.length) {
+            const right = this.heap[rightIndex];
+            const largestNode = this.heap[largest];
+            if (
+                right.priority > largestNode.priority ||
+                (right.priority === largestNode.priority && right.createdAt < largestNode.createdAt)
+            ) {
+                largest = rightIndex;
+            }
+        }
+
+        if (largest !== index) {
+            this.swap(index, largest);
+            this.bubbleDown(largest);
+        }
+    }
+
+    /**
+     * 添加任务到队列
+     * @param {Object} task - 任务对象，必须包含 priority 和 createdAt 属性
+     */
+    push(task) {
+        if (!task.hasOwnProperty('priority')) {
+            task.priority = 5; // 默认优先级
+        }
+        if (!task.hasOwnProperty('createdAt')) {
+            task.createdAt = Date.now();
+        }
+        this.heap.push(task);
+        this.bubbleUp(this.heap.length - 1);
+    }
+
+    /**
+     * 取出优先级最高的任务
+     * @returns {Object|null} 任务对象或null
+     */
+    pop() {
+        if (this.heap.length === 0) {
+            return null;
+        }
+
+        if (this.heap.length === 1) {
+            return this.heap.pop();
+        }
+
+        const top = this.heap[0];
+        this.heap[0] = this.heap.pop();
+        this.bubbleDown(0);
+
+        return top;
+    }
+
+    /**
+     * 查看优先级最高的任务（不移除）
+     * @returns {Object|null} 任务对象或null
+     */
+    peek() {
+        return this.heap.length > 0 ? this.heap[0] : null;
+    }
+
+    /**
+     * 获取队列大小
+     * @returns {number}
+     */
+    size() {
+        return this.heap.length;
+    }
+
+    /**
+     * 检查队列是否为空
+     * @returns {boolean}
+     */
+    isEmpty() {
+        return this.heap.length === 0;
+    }
+
+    /**
+     * 清空队列
+     */
+    clear() {
+        this.heap = [];
+    }
+
+    /**
+     * 查找任务
+     * @param {Function} predicate - 查找条件函数
+     * @returns {Object|null} 任务对象或null
+     */
+    find(predicate) {
+        return this.heap.find(predicate) || null;
+    }
+
+    /**
+     * 移除任务
+     * @param {Function} predicate - 查找条件函数
+     * @returns {boolean} 是否成功移除
+     */
+    remove(predicate) {
+        const index = this.heap.findIndex(predicate);
+        if (index === -1) {
+            return false;
+        }
+
+        if (index === this.heap.length - 1) {
+            this.heap.pop();
+            return true;
+        }
+
+        // 将最后一个元素移到当前位置
+        this.heap[index] = this.heap.pop();
+
+        // 重新调整堆
+        const parentIndex = this.parent(index);
+        if (index > 0 && this.heap[parentIndex] && 
+            (this.heap[index].priority > this.heap[parentIndex].priority ||
+             (this.heap[index].priority === this.heap[parentIndex].priority && 
+              this.heap[index].createdAt < this.heap[parentIndex].createdAt))) {
+            this.bubbleUp(index);
+        } else {
+            this.bubbleDown(index);
+        }
+
+        return true;
+    }
+
+    /**
+     * 转换为数组（用于调试）
+     * @returns {Array}
+     */
+    toArray() {
+        return [...this.heap];
+    }
+}
+
+module.exports = PriorityQueue;
+