From 2765474d9951d3230033d4a45169d40aca950c65 Mon Sep 17 00:00:00 2001
From: kamyu <kamyu104@users.noreply.github.com>
Date: Sun, 1 May 2016 19:41:04 +0800
Subject: [PATCH] Create moving-average-from-data-stream.cpp

---
 C++/moving-average-from-data-stream.cpp | 31 +++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 C++/moving-average-from-data-stream.cpp

diff --git a/C++/moving-average-from-data-stream.cpp b/C++/moving-average-from-data-stream.cpp
new file mode 100644
index 000000000..e4ac8d76e
--- /dev/null
+++ b/C++/moving-average-from-data-stream.cpp
@@ -0,0 +1,31 @@
+// Time:  O(1)
+// Space: O(w)
+
+class MovingAverage {
+public:
+    /** Initialize your data structure here. */
+    MovingAverage(int size) : size_(size), sum_(0) {
+    }
+    
+    double next(int val) {
+        if (q_.size() == size_) {
+            sum_ -= q_.front();
+            q_.pop();
+        }
+        q_.emplace(val);
+        sum_ += val;
+        return 1.0 * sum_ / q_.size();
+    }
+
+private:
+    int size_;
+    int sum_;
+    queue<int> q_;
+};
+
+/**
+ * Your MovingAverage object will be instantiated and called as such:
+ * MovingAverage obj = new MovingAverage(size);
+ * double param_1 = obj.next(val);
+ */
+