Max Sum Subarray of size K Java

PROGRAM TO FIND MAXIMUM SUM OF A SUBARRAY OF SIZE K




import java.util.*;

  

class MAIN {

      

    // Returns maximum sum in a subarray of size k.

    public static int maxSum(int arr[], int n, int k)

    {

        // k must be greater

        if (n < k)

        {

           System.out.println("Invalid");

           return -1;

        }

       

        // Compute sum of first window of size k

        int res = 0;

        for (int i=0; i<k; i++)

           res += arr[i];

       

        // Compute sums of remaining windows by

        // removing first element of previous

        // window and adding last element of 

        // current window.

        int curr_sum = res;

        for (int i=k; i<n; i++)

        {

           curr_sum += arr[i] - arr[i-k];

           res = Math.max(res, curr_sum);

        }

       

        return res;

    }

      

    /* Driver program to test above function */

    public static void main(String[] args) 

    {

        int arr[] = {1, 4, 2, 10, 2, 3, 1, 0, 20};

        int k = 4;

        int n = arr.length;

        System.out.println(maxSum(arr, n, k));

    }

}




OUTPUT:

24

CREDITS: https://www.geeksforgeeks.org/find-maximum-minimum-sum-subarray-size-k/