Create PriorityQueueV2.js

src/PriorityQueueV2.js

@@ -0,0 +1,61 @@
+/**
+ * @param {number[][]} buildings
+ * @return {number[][]}
+ */
+
+class PQ {
+  constructor(comparator) {
+    this.pq = [];
+    this.compare = comparator;
+  }
+
+  get size() {
+    return this.pq.length;
+  }
+
+  swap(i, j) {
+    const pq = this.pq;
+    [pq[i], pq[j]] = [pq[j], pq[i]];
+  }
+
+  siftUp(i) {
+    if (i === 0) return;
+    const pq = this.pq;
+    const j = Math.floor((i - 1) / 2);
+    if (this.better(i, j)) {
+      this.swap(i, j);
+      this.siftUp(j);
+    }
+  }
+  better(i, j) {
+    const pq = this.pq
+    return this.compare(pq[i], pq[j]) < 0
+  }
+  siftDown(i) {
+    const pq = this.pq;
+    const [l, r] = [i * 2 + 1, i * 2 + 2];
+    if (l >= this.size) return;
+    const j = r >= this.size || this.better(l, r) ? l : r;
+    if (this.compare(pq[j], pq[i]) < 0) {
+      this.swap(j, i);
+      this.siftDown(j);
+    }
+  }
+
+  insert(val) {
+    this.pq.push(val);
+    this.siftUp(this.size - 1);
+  }
+
+  peak() {
+    return this.pq[0];
+  }
+
+  pull() {
+    const val = this.pq[0];
+    this.swap(0, this.size - 1);
+    this.pq.pop();
+    this.siftDown(0);
+    return val;
+  }
+}