# Find length of longest subarray with only even elements

Given an array which contains all integer elements, Our goal is to find longest subarray which contains all even numbers. For example

``````Input arr[] = [3 , 9 , 2 , 4 , 4 , 0 , 1 , 3 , 6 , 4 , 2 , 1 , 3 , 9]
Output =  4
Following subarray of even number
[2 , 4 , 4 , 0] length 4
[6 , 4 , 2] length 3

4 is maximum subarray of even numbers
``````

Here given code implementation process.

``````// C program for
// Find length of longest subarray with only even elements
#include <stdio.h>

int longestEvenSubarray(int arr[], int n)
{
int even = 0;
int result = 0;
for (int i = 0; i < n; ++i)
{
if (arr[i] % 2 == 0)
{
// When element is even
even++;
}
else
{
// When element is odd
even = 0;
}
if (even > result)
{
result = even;
}
}
// Return the calculated result
return result;
}
int main(int argc, char
const *argv[])
{
int arr[] = {
3 , 9 , 2 , 4 , 4 , 0 , 1 , 3 , 6 , 4 , 2 , 1 , 3 , 9
};
int n = sizeof(arr) / sizeof(arr[0]);
int result = longestEvenSubarray(arr, n);
// Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
// [2, 4, 4, 0]
// Output : 4
printf("\n Result : %d", result);
return 0;
}``````

#### Output

`` Result : 4``
``````// Java program for
// Longest subarray with even numbers
public class Subarray
{
public int longestEvenSubarray(int[] arr, int n)
{
int even = 0;
int result = 0;
for (int i = 0; i < n; ++i)
{
if (arr[i] % 2 == 0)
{
// When element is even
even++;
}
else
{
// When element is odd
even = 0;
}
if (even > result)
{
result = even;
}
}
// Return the calculated result
return result;
}
public static void main(String[] args)
{
int arr[] = {
3 , 9 , 2 , 4 , 4 , 0 , 1 , 3 , 6 , 4 , 2 , 1 , 3 , 9
};
int n = arr.length;
// Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
// [2, 4, 4, 0]
// Output : 4
System.out.println("\n Result : " + result);
}
}``````

#### Output

`` Result : 4``
``````// Include header file
#include <iostream>
using namespace std;
// C++ program for
// Longest subarray with even numbers
class Subarray
{
public: int longestEvenSubarray(int arr[], int n)
{
int even = 0;
int result = 0;
for (int i = 0; i < n; ++i)
{
if (arr[i] % 2 == 0)
{
// When element is even
even++;
}
else
{
// When element is odd
even = 0;
}
if (even > result)
{
result = even;
}
}
// Return the calculated result
return result;
}
};
int main()
{
int arr[] = {
3 , 9 , 2 , 4 , 4 , 0 , 1 , 3 , 6 , 4 , 2 , 1 , 3 , 9
};
int n = sizeof(arr) / sizeof(arr[0]);
// Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
// [2, 4, 4, 0]
// Output : 4
cout << "\n Result : " << result << endl;
return 0;
}``````

#### Output

`` Result : 4``
``````package main
import "fmt"
// Go program for
// Longest subarray with even numbers

func longestEvenSubarray(arr[] int, n int) int {
var even int = 0
var result int = 0
for i := 0 ; i < n ; i++ {
if arr[i] % 2 == 0 {
// When element is even
even++
} else {
// When element is odd
even = 0
}
if even > result {
result = even
}
}
// Return the calculated result
return result
}
func main() {

var arr = [] int {
3,
9,
2,
4,
4,
0,
1,
3,
6,
4,
2,
1,
3,
9,
}
var n int = len(arr)
var result int = longestEvenSubarray(arr, n)
// Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
// [2, 4, 4, 0]
// Output : 4
fmt.Println("\n Result : ", result)
}``````

#### Output

`` Result : 4``
``````// Include namespace system
using System;
namespace KalkiCode
{
// Csharp program for
// Longest subarray with even numbers
public class Subarray
{
public int longestEvenSubarray(int[] arr, int n)
{
var even = 0;
var result = 0;
for (var i = 0; i < n; ++i)
{
if (arr[i] % 2 == 0)
{
// When element is even
even++;
}
else
{
// When element is odd
even = 0;
}
if (even > result)
{
result = even;
}
}
// Return the calculated result
return result;
}
public static void Main(String[] args)
{
int[] arr = {
3 , 9 , 2 , 4 , 4 , 0 , 1 , 3 , 6 , 4 , 2 , 1 , 3 , 9
};
var n = arr.Length;
// Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
// [2, 4, 4, 0]
// Output : 4
Console.WriteLine("\n Result : " + result.ToString());
}
}
}``````

#### Output

`` Result : 4``
``````<?php
// Php program for
// Longest subarray with even numbers
class Subarray
{
public	function longestEvenSubarray(\$arr, \$n)
{
\$even = 0;
\$result = 0;
for (\$i = 0; \$i < \$n; ++\$i)
{
if (\$arr[\$i] % 2 == 0)
{
// When element is even
\$even++;
}
else
{
// When element is odd
\$even = 0;
}
if (\$even > \$result)
{
\$result = \$even;
}
}
// Return the calculated result
return \$result;
}
public static
function main(\$args)
{
\$arr = array(3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9);
\$n = count(\$arr);
// Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
// [2, 4, 4, 0]
// Output : 4
printf("%s\n", "\n Result : ".strval(\$result));
}
}
Subarray::main(array());``````

#### Output

`` Result : 4``
``````// Node JS program for
// Longest subarray with even numbers
class Subarray
{
longestEvenSubarray(arr, n)
{
var even = 0;
var result = 0;
for (var i = 0; i < n; ++i)
{
if (arr[i] % 2 == 0)
{
// When element is even
even++;
}
else
{
// When element is odd
even = 0;
}
if (even > result)
{
result = even;
}
}
// Return the calculated result
return result;
}
}

function main()
{
var arr = [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9];
var n = arr.length;
// Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
// [2, 4, 4, 0]
// Output : 4
console.log("\n Result : " + result);
}
// Start program execution
main();``````

#### Output

`` Result : 4``
``````#  Python 3 program for
#  Longest subarray with even numbers
class Subarray :
def longestEvenSubarray(self, arr, n) :
even = 0
result = 0
i = 0
while (i < n) :
if (arr[i] % 2 == 0) :
#  When element is even
even += 1
else :
#  When element is odd
even = 0

if (even > result) :
result = even

i += 1

#  Return the calculated result
return result

def main() :
arr = [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
n = len(arr)
#  Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
#  [2, 4, 4, 0]
#  Output : 4
print("\n Result : ", result)

if __name__ == "__main__": main()``````

#### Output

`` Result :  4``
``````#  Ruby program for
#  Longest subarray with even numbers
class Subarray
def longestEvenSubarray(arr, n)
even = 0
result = 0
i = 0
while (i < n)
if (arr[i] % 2 == 0)
#  When element is even
even += 1
else
#  When element is odd
even = 0
end

if (even > result)
result = even
end

i += 1
end

#  Return the calculated result
return result
end

end

def main()
arr = [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
n = arr.length
#  Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
#  [2, 4, 4, 0]
#  Output : 4
print("\n Result : ", result, "\n")
end

main()``````

#### Output

`````` Result : 4
``````
``````// Scala program for
// Longest subarray with even numbers
class Subarray()
{
def longestEvenSubarray(arr: Array[Int], n: Int): Int = {
var even: Int = 0;
var result: Int = 0;
var i: Int = 0;
while (i < n)
{
if (arr(i) % 2 == 0)
{
// When element is even
even += 1;
}
else
{
// When element is odd
even = 0;
}
if (even > result)
{
result = even;
}
i += 1;
}
// Return the calculated result
return result;
}
}
object Main
{
def main(args: Array[String]): Unit = {
var task: Subarray = new Subarray();
var arr: Array[Int] = Array(3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9);
var n: Int = arr.length;
var result: Int = task.longestEvenSubarray(arr, n);
// Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
// [2, 4, 4, 0]
// Output : 4
println("\n Result : " + result);
}
}``````

#### Output

`` Result : 4``
``````import Foundation;
// Swift 4 program for
// Longest subarray with even numbers
class Subarray
{
func longestEvenSubarray(_ arr: [Int], _ n: Int) -> Int
{
var even: Int = 0;
var result: Int = 0;
var i: Int = 0;
while (i < n)
{
if (arr[i] % 2 == 0)
{
// When element is even
even += 1;
}
else
{
// When element is odd
even = 0;
}
if (even > result)
{
result = even;
}
i += 1;
}
// Return the calculated result
return result;
}
}
func main()
{
let arr: [Int] = [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9];
let n: Int = arr.count;
let result: Int = task.longestEvenSubarray(arr, n);
// Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
// [2, 4, 4, 0]
// Output : 4
print("\n Result : ", result);
}
main();``````

#### Output

`` Result :  4``
``````// Kotlin program for
// Longest subarray with even numbers
class Subarray
{
fun longestEvenSubarray(arr: Array < Int > , n: Int): Int
{
var even: Int = 0;
var result: Int = 0;
var i: Int = 0;
while (i < n)
{
if (arr[i] % 2 == 0)
{
// When element is even
even += 1;
}
else
{
// When element is odd
even = 0;
}
if (even > result)
{
result = even;
}
i += 1;
}
// Return the calculated result
return result;
}
}
fun main(args: Array < String > ): Unit
{
val arr: Array < Int > = arrayOf(3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9);
val n: Int = arr.count();
val result: Int = task.longestEvenSubarray(arr, n);
// Input : [3, 9, 2, 4, 4, 0, 1, 3, 6, 4, 2, 1, 3, 9]
// [2, 4, 4, 0]
// Output : 4
println("\n Result : " + result);
}``````

#### Output

`` Result : 4``

## Comment

Please share your knowledge to improve code and content standard. Also submit your doubts, and test case. We improve by your feedback. We will try to resolve your query as soon as possible.