Update Solution.cs

Author: yanglbme

solution/0200-0299/0295.Find Median from Data Stream/Solution.cs

@@ -1,50 +1,21 @@
 public class MedianFinder {
-    private List<int> nums;
-    private int curIndex;
+    private PriorityQueue<int, int> minQ = new PriorityQueue<int, int>();
+    private PriorityQueue<int, int> maxQ = new PriorityQueue<int, int>(Comparer<int>.Create((a, b) => b.CompareTo(a)));
 
-    /** initialize your data structure here. */
     public MedianFinder() {
-        nums = new List<int>();
-    }
 
-    private int FindIndex(int val) {
-        int left = 0;
-        int right = nums.Count - 1;
-        while (left <= right) {
-            int mid = left + (right - left) / 2;
-            if (val > nums[mid]) {
-                left = mid + 1;
-            } else {
-                right = mid - 1;
-            }
-        }
-        return left;
     }
 
     public void AddNum(int num) {
-        if (nums.Count == 0) {
-            nums.Add(num);
-            curIndex = 0;
-        } else {
-            curIndex = FindIndex(num);
-            if (curIndex == nums.Count) {
-                nums.Add(num);
-            } else {
-                nums.Insert(curIndex, num);
-            }
+        maxQ.Enqueue(num, num);
+        minQ.Enqueue(maxQ.Peek(), maxQ.Dequeue());
+        if (minQ.Count > maxQ.Count + 1) {
+            maxQ.Enqueue(minQ.Peek(), minQ.Dequeue());
         }
     }
 
     public double FindMedian() {
-        if (nums.Count % 2 == 1) {
-            return (double)nums[nums.Count / 2];
-        } else {
-            if (nums.Count == 0) {
-                return 0;
-            } else {
-                return (double) (nums[nums.Count / 2 - 1] + nums[nums.Count / 2]) / 2;
-            }
-        }
+        return minQ.Count == maxQ.Count ? (minQ.Peek() + maxQ.Peek()) / 2.0 : minQ.Peek();
     }
 }