Update README_EN.md

Author: yanglbme

solution/0700-0799/0731.My Calendar II/README_EN.md

@@ -206,6 +206,43 @@ func (this *MyCalendarTwo) Book(start int, end int) bool {
  */
 ```
 
+#### JavaScript
+
+```js
+var MyCalendarTwo = function () {
+    this.events = [];
+    this.overlaps = [];
+};
+
+/**
+ * @param {number} start
+ * @param {number} end
+ * @return {boolean}
+ */
+MyCalendarTwo.prototype.book = function (start, end) {
+    for (let [s, e] of this.overlaps) {
+        if (Math.max(start, s) < Math.min(end, e)) {
+            return false;
+        }
+    }
+
+    for (let [s, e] of this.events) {
+        if (Math.max(start, s) < Math.min(end, e)) {
+            this.overlaps.push([Math.max(start, s), Math.min(end, e)]);
+        }
+    }
+
+    this.events.push([start, end]);
+    return true;
+};
+
+/**
+ * Your MyCalendarTwo object will be instantiated and called as such:
+ * var obj = new MyCalendarTwo()
+ * var param_1 = obj.book(start,end)
+ */
+```
+
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