Create 1801-number-of-orders-in-the-backlog.js

Author: everthis

1801-number-of-orders-in-the-backlog.js

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+/**
+ * @param {number[][]} orders
+ * @return {number}
+ */
+const getNumberOfBacklogOrders = function (orders) {
+  const h0 = new PriorityQueue((a, b) => a[0] > b[0])
+  const h1 = new PriorityQueue((a, b) => a[0] > b[0])
+  const P = 10 ** 9 + 7
+  const { min } = Math
+
+  while (!h0.isEmpty()) h0.pop()
+  while (!h1.isEmpty()) h1.pop()
+  let i,
+    j,
+    i1,
+    j1,
+    ans = 0
+  for (let c of orders) {
+    i = c[0]
+    j = c[1]
+    if (c[2]) {
+      while (!h0.isEmpty() && h0.peek()[0] >= i) {
+        i1 = h0.peek()[0]
+        j1 = h0.peek()[1]
+        h0.pop()
+        if (j > j1) j -= j1
+        else {
+          j1 -= j
+          j = 0
+          if (j1) h0.push([i1, j1])
+          break
+        }
+      }
+      if (j) h1.push([-i, j])
+    } else {
+      while (!h1.isEmpty() && -h1.peek()[0] <= i) {
+        i1 = h1.peek()[0]
+        j1 = h1.peek()[1]
+        h1.pop()
+        if (j > j1) j -= j1
+        else {
+          j1 -= j
+          j = 0
+          if (j1) h1.push([i1, j1])
+          break
+        }
+      }
+      if (j) h0.push([i, j])
+    }
+  }
+  while (!h0.isEmpty()) {
+    ans += h0.peek()[1]
+    h0.pop()
+    if (ans >= P) ans -= P
+  }
+  while (!h1.isEmpty()) {
+    ans += h1.peek()[1]
+    h1.pop()
+    if (ans >= P) ans -= P
+  }
+  return ans
+}
+
+class PriorityQueue {
+  constructor(comparator = (a, b) => a > b) {
+    this.heap = []
+    this.top = 0
+    this.comparator = comparator
+  }
+  size() {
+    return this.heap.length
+  }
+  isEmpty() {
+    return this.size() === 0
+  }
+  peek() {
+    return this.heap[this.top]
+  }
+  push(...values) {
+    values.forEach((value) => {
+      this.heap.push(value)
+      this.siftUp()
+    })
+    return this.size()
+  }
+  pop() {
+    const poppedValue = this.peek()
+    const bottom = this.size() - 1
+    if (bottom > this.top) {
+      this.swap(this.top, bottom)
+    }
+    this.heap.pop()
+    this.siftDown()
+    return poppedValue
+  }
+  replace(value) {
+    const replacedValue = this.peek()
+    this.heap[this.top] = value
+    this.siftDown()
+    return replacedValue
+  }
+
+  parent = (i) => ((i + 1) >>> 1) - 1
+  left = (i) => (i << 1) + 1
+  right = (i) => (i + 1) << 1
+  greater = (i, j) => this.comparator(this.heap[i], this.heap[j])
+  swap = (i, j) => ([this.heap[i], this.heap[j]] = [this.heap[j], this.heap[i]])
+  siftUp = () => {
+    let node = this.size() - 1
+    while (node > this.top && this.greater(node, this.parent(node))) {
+      this.swap(node, this.parent(node))
+      node = this.parent(node)
+    }
+  }
+  siftDown = () => {
+    let node = this.top
+    while (
+      (this.left(node) < this.size() && this.greater(this.left(node), node)) ||
+      (this.right(node) < this.size() && this.greater(this.right(node), node))
+    ) {
+      let maxChild =
+        this.right(node) < this.size() &&
+        this.greater(this.right(node), this.left(node))
+          ? this.right(node)
+          : this.left(node)
+      this.swap(node, maxChild)
+      node = maxChild
+    }
+  }
+}