Add solution #295

Author: JoshCrozier

README.md

@@ -173,6 +173,7 @@
 278|[First Bad Version](./0278-first-bad-version.js)|Medium|
 283|[Move Zeroes](./0283-move-zeroes.js)|Easy|
 290|[Word Pattern](./0290-word-pattern.js)|Easy|
+295|[Find Median from Data Stream](./0295-find-median-from-data-stream.js)|Hard|
 316|[Remove Duplicate Letters](./0316-remove-duplicate-letters.js)|Medium|
 326|[Power of Three](./0326-power-of-three.js)|Easy|
 328|[Odd Even Linked List](./0328-odd-even-linked-list.js)|Medium|

solutions/0295-find-median-from-data-stream.js

@@ -0,0 +1,44 @@
+/**
+ * 295. Find Median from Data Stream
+ * https://leetcode.com/problems/find-median-from-data-stream/
+ * Difficulty: Hard
+ *
+ * The median is the middle value in an ordered integer list. If the size of the list is
+ * even, there is no middle value, and the median is the mean of the two middle values.
+ *
+ * - For example, for arr = [2,3,4], the median is 3.
+ * - For example, for arr = [2,3], the median is (2 + 3) / 2 = 2.5.
+ *
+ * Implement the MedianFinder class:
+ * - MedianFinder() initializes the MedianFinder object.
+ * - void addNum(int num) adds the integer num from the data stream to the data structure.
+ * - double findMedian() returns the median of all elements so far. Answers within 10-5 of
+ *   the actual answer will be accepted.
+ */
+
+
+var MedianFinder = function() {
+  this.minHeap = new MinPriorityQueue();
+  this.maxHeap = new MaxPriorityQueue();
+};
+
+/**
+ * @param {number} num
+ * @return {void}
+ */
+MedianFinder.prototype.addNum = function(num) {
+  this.minHeap.enqueue(num);
+  this.maxHeap.enqueue(this.minHeap.dequeue().element);
+  if (this.minHeap.size() < this.maxHeap.size()) {
+    this.minHeap.enqueue(this.maxHeap.dequeue().element);
+  }
+};
+
+/**
+ * @return {number}
+ */
+MedianFinder.prototype.findMedian = function() {
+  return this.minHeap.size() > this.maxHeap.size()
+    ? this.minHeap.front().element
+    : (this.minHeap.front().element + this.maxHeap.front().element) / 2;
+};