Program to find simple moving average | Set-2

Simple Moving Average is the average obtained from the data for some t period of time . In normal mean, its value get changed with the changing data but in this type of mean it also changes with the time interval. We get the mean for some period t and then we remove some previous data. Again we get new mean and this process continues. This is why it is moving average. This has a great application in the financial market. OR this can be simply visualized as follows.

Given an arr[] of size N, containing only positive integers and an integer K. The task is to compute the simple moving average of previous K elements.

Examples:

Input: { 1, 3, 5, 6, 8 }, K = 3
Output: 0.33 1.33 3.00 4.67 6.33
Explanation: New number added is 1.0, SMA = 0.33
New number added is 3.0, SMA = 1.33
New number added is 5.0, SMA = 3.0
New number added is 6.0, SMA = 4.67
New number added is 8.0, SMA = 6.33

Input: Array[]= {2, 5, 7, 3, 11, 9, 13, 12}, K = 2
Output: 1.0 3.5 6 5 7 10 11 12.5

Naive Approach: This uses two nested loops. Outer loop traverses the array from left to right. Inner loop computes the average of K previous elements including itself for each index. Finally, the moving average values are printed. The outer loop starts traversal from index K itself. Instead of storing the result, we can directly display the output to avoid using extra spaces.

Time complexity: O(N*K)
Space complexity: O(1)

Efficient Approach: The efficient approach is discussed in the Set-1 of this problem.

Space Optimized approach: This uses sliding window for better time efficiency and space optimization. A window of size K starts from index K and the moving average is printed for each index thereafter.

Below is the implementation of the above approach.

C++

 // C++ code to find the simple moving average #include #include using namespace std;   // Function to compute moving average // of previous K elements void ComputeMovingAverage(int arr[], int N,                           int K) {     int i;     float sum = 0;       // Initial sum of K elements.     for (i = 0; i < K; i++) {         sum += arr[i];         cout << setprecision(2) << std::fixed;         cout << sum / K << " ";     }       // Compute MA from index K     float avg;     for (i = K; i < N; i++) {         sum -= arr[i - K];         sum += arr[i];         avg = sum / K;         cout << setprecision(2) << std::fixed;         cout << avg << " ";     } }   // Driver code int main() {     int arr[] = { 1, 3, 5, 6, 8 };     int N = sizeof(arr) / sizeof(arr[0]);     int K = 3;     ComputeMovingAverage(arr, N, K);     return 0; }

Java

 // Java code to find the simple moving average import java.util.*; class GFG{     // Function to compute moving average   // of previous K elements   static void ComputeMovingAverage(int arr[], int N,                                    int K)   {     int i;     float sum = 0;       // Initial sum of K elements.     for (i = 0; i < K; i++) {       sum += arr[i];       System.out.printf("%.2f ",sum / K);     }       // Compute MA from index K     for (i = K; i < N; i++) {       sum -= arr[i - K];       sum += arr[i];       System.out.printf("%.2f ",sum / K);     }   }     // Driver code   public static void main(String[] args)   {     int arr[] = { 1, 3, 5, 6, 8 };     int N = arr.length;     int K = 3;     ComputeMovingAverage(arr, N, K);   } }   // This code is contributed by Rajput-Ji

Python3

 # Python code for the above approach   # Function to compute moving average # of previous K elements def ComputeMovingAverage(arr, N, K):     i = None     sum = 0       # Initial sum of K elements.     for i in range(K):         sum += arr[i]         print("%.2f"%(sum / K), end= " ")       # Compute MA from index K     for i in range(K, N):         sum -= arr[i - K]         sum += arr[i]         avg = sum / K         print("%.2f"%(avg), end =" ")   # Driver code arr = [1, 3, 5, 6, 8] N = len(arr) K = 3 ComputeMovingAverage(arr, N, K)   # This code is contributed by Saurabh Jaiswal

C#

 // C# code to find the simple moving average using System;   class GFG {     // Function to compute moving average   // of previous K elements   static void ComputeMovingAverage(int[] arr, int N,                                    int K)   {     int i;     float sum = 0;       // Initial sum of K elements.     for (i = 0; i < K; i++) {       sum += arr[i];       Console.Write(Math.Round((sum / K),2) + " ");     }       // Compute MA from index K     for (i = K; i < N; i++) {       sum -= arr[i - K];       sum += arr[i];       Console.Write(Math.Round(sum / K, 2) + " ");     }   }     // Driver code   public static void Main(string[] args)   {     int[] arr = { 1, 3, 5, 6, 8 };     int N = arr.Length;     int K = 3;     ComputeMovingAverage(arr, N, K);   } }   // This code is contributed by ukasp.

Javascript



Output

0.33 1.33 3.00 4.67 6.33

Time complexity: O(N)
Space complexity: O(1)

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