solve find median from data stream

Author: sora0319

find-median-from-data-stream/sora0319.java

@@ -0,0 +1,26 @@
+public class MedianFinder {
+    private PriorityQueue<Integer> maxHeap;
+    private PriorityQueue<Integer> minHeap;
+
+    public MedianFinder() {
+        maxHeap = new PriorityQueue<>(Collections.reverseOrder());
+        minHeap = new PriorityQueue<>();
+    }
+
+    public void addNum(int num) {
+        maxHeap.offer(num);
+        minHeap.offer(maxHeap.poll());
+
+        if (minHeap.size() > maxHeap.size()) {
+            maxHeap.offer(minHeap.poll());
+        }
+    }
+
+    public double findMedian() {
+        if (maxHeap.size() > minHeap.size()) {
+            return maxHeap.peek();
+        } else {
+            return (maxHeap.peek() + minHeap.peek()) / 2.0;
+        }
+    }
+}