Sum of elements till the smallest index such that there are no even numbers to its right

Given an array arr[] of N integers. The task is to find the sum of elements till the smallest index such that there are no even elements to the right of the index. Note that the array will have at least one even element.

Examples:

Input: arr[] = {2, 3, 5, 6, 3, 3}
Output: 16
2 + 3 + 5 + 6 = 16

Input: arr[] = {3, 4}
Output: 7
3 + 4 = 7

Approach: Find the index of the rightmost even element from the array and return the sum of all the elements starting from index 0 till the found index.



Below is the implementation of the above approach:

C++

filter_none

edit
close

play_arrow

link
brightness_4
code

// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;
  
// Function to return the required sum
int smallestIndexsum(int arr[], int n)
{
  
    // Starting from the last index
    int i = n - 1;
  
    // Skip all odd elements and find the
    // index of the righmost even element
    while (i >= 0 && arr[i] % 2 == 1)
        i--;
  
    // To store the requried sum
    int sum = 0;
    for (int j = 0; j <= i; j++)
        sum += arr[j];
  
    return sum;
}
  
// Driver code
int main()
{
  
    int arr[] = { 2, 3, 5, 6, 3, 3 };
    int n = sizeof(arr) / sizeof(arr[0]);
  
    cout << smallestIndexsum(arr, n);
  
    return 0;
}

chevron_right


Java

filter_none

edit
close

play_arrow

link
brightness_4
code

// Java implementation of the approach
class GFG 
{
  
// Function to return the required sum
static int smallestIndexsum(int arr[], int n)
{
  
    // Starting from the last index
    int i = n - 1;
  
    // Skip all odd elements and find the
    // index of the righmost even element
    while (i >= 0 && arr[i] % 2 == 1)
        i--;
  
    // To store the requried sum
    int sum = 0;
    for (int j = 0; j <= i; j++)
        sum += arr[j];
  
    return sum;
}
  
// Driver code
public static void main(String[] args) 
{
    int arr[] = { 2, 3, 5, 6, 3, 3 };
    int n = arr.length;
  
    System.out.println(smallestIndexsum(arr, n));
}
  
// This code is contributed by 29AjayKumar

chevron_right


Python3

filter_none

edit
close

play_arrow

link
brightness_4
code

# Python3 implementation of the approach
  
# Function to return the required sum
def smallestIndexsum(arr, n):
  
    # Starting from the last index
    i = n - 1;
  
    # Skip all odd elements and find the
    # index of the righmost even element
    while (i >= 0 and arr[i] % 2 == 1):
        i -= 1;
  
    # To store the requried sum
    sum = 0;
    for j in range(0, i + 1):
        sum += arr[j];
  
    return sum;
  
# Driver code
if __name__ == '__main__':
  
    arr = [ 2, 3, 5, 6, 3, 3 ];
    n = len(arr);
  
    print(smallestIndexsum(arr, n));
  
# This code is contributed by PrinciRaj1992

chevron_right


C#

filter_none

edit
close

play_arrow

link
brightness_4
code

// C# implementation of the approach
using System;
  
class GFG
{
      
// Function to return the required sum
static int smallestIndexsum(int []arr, int n)
{
  
    // Starting from the last index
    int i = n - 1;
  
    // Skip all odd elements and find the
    // index of the righmost even element
    while (i >= 0 && arr[i] % 2 == 1)
        i--;
  
    // To store the requried sum
    int sum = 0;
    for (int j = 0; j <= i; j++)
        sum += arr[j];
  
    return sum;
}
  
// Driver code
static public void Main ()
{
    int []arr = { 2, 3, 5, 6, 3, 3 };
    int n = arr.Length;
      
    Console.Write(smallestIndexsum(arr, n));
}
  
// This code is contributed by ajit.

chevron_right


Output:

16

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.




My Personal Notes arrow_drop_up

Recommended Posts:


Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.



Article Tags :
Practice Tags :


Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.