Create 2276-count-integers-in-intervals.js

Author: everthis

2276-count-integers-in-intervals.js

@@ -0,0 +1,78 @@
+var CountIntervals = function () {
+  this.root = new Node(1, 10 ** 9)
+}
+
+/**
+ * @param {number} left
+ * @param {number} right
+ * @return {void}
+ */
+CountIntervals.prototype.add = function (left, right) {
+  this.root.addInterval(left, right)
+}
+
+/**
+ * @return {number}
+ */
+CountIntervals.prototype.count = function () {
+  return this.root.total
+}
+
+/**
+ * Your CountIntervals object will be instantiated and called as such:
+ * var obj = new CountIntervals()
+ * obj.add(left,right)
+ * var param_2 = obj.count()
+ */
+
+class Node {
+  constructor(min, max) {
+    this.min = min
+    this.max = max
+    this.currentMin = -1
+    this.currentMax = -1
+    this.total = 0
+    this.left = null
+    this.right = null
+  }
+
+  addInterval(left, right) {
+    if (this.currentMin < 0) {
+      this.currentMin = left
+      this.currentMax = right
+      this.total = right - left + 1
+      return this.total
+    }
+
+    const mid = (this.min + this.max) >> 1
+
+    if (this.left) {
+      if (left <= mid) this.left.addInterval(left, Math.min(mid, right))
+      if (right > mid) this.right.addInterval(Math.max(mid + 1, left), right)
+
+      this.total = this.left.total + this.right.total
+      return
+    }
+
+    if (left <= this.currentMax + 1 && right >= this.currentMin - 1) {
+      this.currentMin = Math.min(this.currentMin, left)
+      this.currentMax = Math.max(this.currentMax, right)
+      this.total = this.currentMax - this.currentMin + 1
+      return
+    }
+    this.left = new Node(this.min, mid)
+    this.right = new Node(mid + 1, this.max)
+
+    if (left <= mid) this.left.addInterval(left, Math.min(mid, right))
+    if (right > mid) this.right.addInterval(Math.max(left, mid + 1), right)
+    if (this.currentMin <= mid)
+      this.left.addInterval(this.currentMin, Math.min(mid, this.currentMax))
+    if (this.currentMax > mid)
+      this.right.addInterval(
+        Math.max(mid + 1, this.currentMin),
+        this.currentMax
+      )
+
+    this.total = this.left.total + this.right.total
+  }
+}