Revert "Delete 295-Find-Median-from-Data-Stream.js - Duplicate File"

Author: aakhtar3

Diff for: javascript/295-Find-Median-from-Data-Stream.js

@@ -0,0 +1,56 @@
+/** 
+ * https://leetcode.com/problems/find-median-from-data-stream/
+ * Your MedianFinder object will be instantiated and called as such:
+ * var obj = new MedianFinder()
+ * obj.addNum(num)
+ * var param_2 = obj.findMedian()
+ */
+class MedianFinder {
+    constructor () {
+        this.maxHeap = new MaxPriorityQueue()
+        this.minHeap = new MinPriorityQueue()
+    }
+
+    /* Time O(log(N)) | Space (N) */
+    insertNum (num) {
+        this.addNum(num)
+    }
+
+    addNum (num, heap = this.getHeap(num)) {
+        heap.enqueue(num)
+        this.rebalance()
+    }
+
+    getHeap (num, { maxHeap, minHeap } = this) {
+        const isFirst = maxHeap.isEmpty()
+        const isGreater = num <= this.top(maxHeap);
+        const isMaxHeap = (isFirst || isGreater);
+        return (isMaxHeap)
+            ? maxHeap
+            : minHeap
+    }
+
+    rebalance ({ maxHeap, minHeap } = this) {
+        const canShiftMax = (minHeap.size() + 1) < maxHeap.size()
+        if (canShiftMax) return minHeap.enqueue(maxHeap.dequeue().element)
+
+        const canShiftMin = maxHeap.size() < minHeap.size()
+        if (canShiftMin) return maxHeap.enqueue(minHeap.dequeue().element)
+    }
+
+    /* Time O(1) | Space (1) */
+    findMedian ({ maxHeap, minHeap } = this) {
+        const isEven = maxHeap.size() === minHeap.size()
+        return (isEven)
+            ? this.average(maxHeap, minHeap)
+            : this.top(maxHeap)
+    }
+
+    average (maxHeap, minHeap) {
+        return (this.top(maxHeap) + this.top(minHeap)) / 2
+    }
+
+    top (heap) {
+        return heap.front()?.element || 0
+    }
+}