Add solution #731

Author: JoshCrozier

README.md

@@ -554,6 +554,7 @@
 728|[Self Dividing Numbers](./0728-self-dividing-numbers.js)|Easy|
 729|[My Calendar I](./0729-my-calendar-i.js)|Medium|
 730|[Count Different Palindromic Subsequences](./0730-count-different-palindromic-subsequences.js)|Hard|
+731|[My Calendar II](./0731-my-calendar-ii.js)|Medium|
 733|[Flood Fill](./0733-flood-fill.js)|Easy|
 735|[Asteroid Collision](./0735-asteroid-collision.js)|Medium|
 739|[Daily Temperatures](./0739-daily-temperatures.js)|Medium|

solutions/0731-my-calendar-ii.js

@@ -0,0 +1,46 @@
+/**
+ * 731. My Calendar II
+ * https://leetcode.com/problems/my-calendar-ii/
+ * Difficulty: Medium
+ *
+ * You are implementing a program to use as your calendar. We can add a new event if adding the
+ * event will not cause a triple booking.
+ *
+ * A triple booking happens when three events have some non-empty intersection (i.e., some moment
+ * is common to all the three events.).
+ *
+ * The event can be represented as a pair of integers startTime and endTime that represents a
+ * booking on the half-open interval [startTime, endTime), the range of real numbers x such that
+ * startTime <= x < endTime.
+ *
+ * Implement the MyCalendarTwo class:
+ * - MyCalendarTwo() Initializes the calendar object.
+ * - boolean book(int startTime, int endTime) Returns true if the event can be added to the calendar
+ *   successfully without causing a triple booking. Otherwise, return false and do not add the event
+ *   to the calendar.
+ */
+
+var MyCalendarTwo = function() {
+  this.bookings = [];
+  this.overlaps = [];
+};
+
+/**
+ * @param {number} startTime
+ * @param {number} endTime
+ * @return {boolean}
+ */
+MyCalendarTwo.prototype.book = function(startTime, endTime) {
+  for (const [start, end] of this.overlaps) {
+    if (startTime < end && endTime > start) return false;
+  }
+
+  for (const [start, end] of this.bookings) {
+    if (startTime < end && endTime > start) {
+      this.overlaps.push([Math.max(start, startTime), Math.min(end, endTime)]);
+    }
+  }
+
+  this.bookings.push([startTime, endTime]);
+  return true;
+};