solves #346: Moving Average from data stream in java

Author: anishLearnsToCode

README.md

@@ -293,7 +293,7 @@
 | 343  | [Integer Break](https://leetcode.com/problems/integer-break)                                                                                                           |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 344  | [Reverse A String](https://leetcode.com/problems/reverse-string)                                                                                                       |                                                          [![Java](assets/java.png)](src/ReverseString.java) [![Python](assets/python.png)](python/reverse_a_string.py)                                                           |                                                                                                                                   |
 | 345  | [Reverse Vowels of A String](https://leetcode.com/problems/reverse-vowels-of-a-string)                                                                                 |                                                 [![Java](assets/java.png)](src/ReverseVowelsOfString.java) [![Python](assets/python.png)](python/reverse_vowels_of_a_string.py)                                                  |                                                                                                                                   |
-| 346  | 🔒 [Moving Average From Data Stream](https://leetcode.com/problems/moving-average-from-data-stream)                                                                    |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 346  | 🔒 [Moving Average From Data Stream](https://leetcode.com/problems/moving-average-from-data-stream)                                                                    |                                                                                 [![Java](assets/java.png)](src/MovingAverageFromDataStream.java)                                                                                 |                                                                                                                                   |
 | 347  | [Top K frequent Elements](https://leetcode.com/problems/top-k-frequent-elements)                                                                                       |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 348  | 🔒 [Design Tic-Tac-Toe](https://leetcode.com/problems/design-tic-tac-toe)                                                                                              |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 349  | [Intersection of 2 Arrays](https://leetcode.com/problems/intersection-of-two-arrays)                                                                                   |                                                  [![Java](assets/java.png)](src/IntersectionOfTwoArrays.java) [![Python](assets/python.png)](python/intersection_of_2_array.py)                                                  |                                                                                                                                   |

src/MovingAverageFromDataStream.java

@@ -0,0 +1,31 @@
+// https://leetcode.com/problems/moving-average-from-data-stream
+// N: number of calls to next(), M: max window size
+// T: O(N)
+// S: O(M)
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class MovingAverageFromDataStream {
+}
+
+
+class MovingAverage {
+    final int windowSize;
+    final Queue<Integer> queue = new LinkedList<>();
+    double windowSum = 0;
+
+    // T: O(1)
+    public MovingAverage(int size) {
+        windowSize = size;
+    }
+
+    // T: O(1)
+    // S: O(1)
+    public double next(int val) {
+        queue.add(val);
+        final int toRemove = (queue.size() > windowSize && !queue.isEmpty()) ? queue.poll() : 0;
+        windowSum += val - toRemove;
+        return windowSum / queue.size();
+    }
+}