# Find if it is possible to choose subarray that it contains exactly K even integers

Given 2 positive integers N and K and an array arr[], the task is to find whether it is possible to choose a non-empty subarray of the array such that the subarray contains exactly K even integers.

Examples:

Input: N = 4, K = 2, arr[] = {1, 2, 4, 5}
Output: Yes
Explanation:
We can select the subarray {2, 4} which contains exactly K = 2 even numbers.

Input: N = 3, K = 3, arr[] = {2, 4, 5}
Output: No
Explanation:
There are only two even numbers. Therefore, we cannot choose a subarray with K = 3 even numbers.

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: The idea is to count the number of even numbers in the array. Now there can be 3 cases:

• If the count of even numbers in the array is 0 (i.e.) there are only odd numbers in the array, then we can’t select any subarray
• If the count of even numbers in the array is ≥ K, then we can easily select a subarray with exactly K even integers
• Else it is not possible to select a subarray with exactly K even integers

Below is the implementation of the above approach:

## CPP

 `// C++ program to check if it is possible to ` `// choose a subarray that contains exactly ` `// K even integers ` `#include ` `using` `namespace` `std; ` ` `  `// Function to check if it is possible to ` `// choose a subarray that contains exactly ` `// K even integers ` `void` `isPossible(``int` `A[], ``int` `n, ``int` `k) ` `{ ` `    ``// Variable to store the count of ` `    ``// even numbers ` `    ``int` `countOfTwo = 0; ` `    ``for` `(``int` `i = 0; i < n; i++) { ` `        ``if` `(A[i] % 2 == 0) { ` `            ``countOfTwo++; ` `        ``} ` `    ``} ` ` `  `    ``// If we have to select 0 even numbers ` `    ``// but there is all odd numbers in the array ` `    ``if` `(k == 0 && countOfTwo == n) ` `        ``cout << ``"NO\n"``; ` ` `  `    ``// If the count of even numbers is greater than ` `    ``// or equal to K then we can select a ` `    ``// subarray with exactly K even integers ` `    ``else` `if` `(countOfTwo >= k) { ` `        ``cout << ``"Yes\n"``; ` `    ``} ` ` `  `    ``// If the count of even numbers is less than K ` `    ``// then we cannot select any subarray with ` `    ``// exactly K even integers ` `    ``else` `        ``cout << ``"No\n"``; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``int` `arr[] = { 1, 2, 4, 5 }; ` `    ``int` `K = 2; ` `    ``int` `N = ``sizeof``(arr) / ``sizeof``(arr); ` ` `  `    ``isPossible(arr, N, K); ` `    ``return` `0; ` `} `

## Java

 `// Java program to check if it is possible to ` `// choose a subarray that contains exactly ` `// K even integers ` `import` `java.util.*; ` `  `  `class` `GFG{ ` `// Function to check if it is possible to ` `// choose a subarray that contains exactly ` `// K even integers ` `static` `void` `isPossible(``int` `[]A, ``int` `n, ``int` `k) ` `{ ` `    ``// Variable to store the count of ` `    ``// even numbers ` `    ``int` `countOfTwo = ``0``; ` `    ``for` `(``int` `i = ``0``; i < n; i++) { ` `        ``if` `(A[i] % ``2` `== ``0``) { ` `            ``countOfTwo++; ` `        ``} ` `    ``} ` ` `  `    ``// If we have to select 0 even numbers ` `    ``// but there is all odd numbers in the array ` `    ``if` `(k == ``0` `&& countOfTwo == n) ` `        ``System.out.print(``"NO"``); ` ` `  `    ``// If the count of even numbers is greater than ` `    ``// or equal to K then we can select a ` `    ``// subarray with exactly K even integers ` `    ``else` `if` `(countOfTwo >= k) { ` `        ``System.out.print(``"YES"``); ` `    ``} ` ` `  `    ``// If the count of even numbers is less than K ` `    ``// then we cannot select any subarray with ` `    ``// exactly K even integers ` `    ``else` `        ``System.out.print(``"No"``); ` `} ` ` `  `// Driver Code ` `public` `static` `void` `main(String[] args) ` `{ ` `    ``int` `[]arr = { ``1``, ``2``, ``4``, ``5` `}; ` `    ``int` `K = ``2``; ` `    ``int` `n = arr.length; ` ` `  `    ``isPossible(arr, n, K); ` `} ` `} ` ` `  `// This code is contributed by shivanisinghss2110 `

## Python3

 `# Python3 program to check if it is possible to ` `# choose a subarray that contains exactly ` `# K even integers ` ` `  `# Function to check if it is possible to ` `# choose a subarray that contains exactly ` `# K even integers ` `def` `isPossible(A, n, k): ` `     `  `    ``# Variable to store the count of ` `    ``# even numbers ` `    ``countOfTwo ``=` `0` `    ``for` `i ``in` `range``(n): ` `        ``if` `(A[i] ``%` `2` `=``=` `0``): ` `            ``countOfTwo ``+``=` `1` ` `  `    ``# If we have to select 0 even numbers ` `    ``# but there is all odd numbers in the array ` `    ``if` `(k ``=``=` `0` `and` `countOfTwo ``=``=` `n): ` `        ``print``(``"NO\n"``) ` ` `  `    ``# If the count of even numbers is greater than ` `    ``# or equal to K then we can select a ` `    ``# subarray with exactly K even integers ` `    ``elif` `(countOfTwo >``=` `k): ` `        ``print``(``"Yes\n"``) ` ` `  `    ``# If the count of even numbers is less than K ` `    ``# then we cannot select any subarray with ` `    ``# exactly K even integers ` `    ``else``: ` `        ``print``(``"No\n"``) ` ` `  `# Driver code ` `if` `__name__ ``=``=` `'__main__'``: ` `    ``arr``=``[``1``, ``2``, ``4``, ``5``] ` `    ``K ``=` `2` `    ``N ``=` `len``(arr) ` ` `  `    ``isPossible(arr, N, K) ` ` `  `# This code is contributed by mohit kumar 29 `

## C#

 `// C# program to check if it is possible to ` `// choose a subarray that contains exactly ` `// K even integers ` `using` `System; ` ` `  `class` `GFG{ ` ` `  `// Function to check if it is possible to ` `// choose a subarray that contains exactly ` `// K even integers ` `static` `void` `isPossible(``int` `[]A, ``int` `n, ``int` `k) ` `{ ` `    ``// Variable to store the count of ` `    ``// even numbers ` `    ``int` `countOfTwo = 0; ` `    ``for` `(``int` `i = 0; i < n; i++) { ` `        ``if` `(A[i] % 2 == 0) { ` `            ``countOfTwo++; ` `        ``} ` `    ``} ` ` `  `    ``// If we have to select 0 even numbers ` `    ``// but there is all odd numbers in the array ` `    ``if` `(k == 0 && countOfTwo == n) ` `        ``Console.Write(``"NO"``); ` ` `  `    ``// If the count of even numbers is greater than ` `    ``// or equal to K then we can select a ` `    ``// subarray with exactly K even integers ` `    ``else` `if` `(countOfTwo >= k) { ` `        ``Console.Write(``"Yes"``); ` `    ``} ` ` `  `    ``// If the count of even numbers is less than K ` `    ``// then we cannot select any subarray with ` `    ``// exactly K even integers ` `    ``else` `        ``Console.Write(``"No"``); ` `} ` ` `  `// Driver Code ` `public` `static` `void` `Main() ` `{ ` `    ``int` `[]arr = { 1, 2, 4, 5 }; ` `    ``int` `K = 2; ` `    ``int` `n = arr.Length; ` ` `  `    ``isPossible(arr, n, K); ` `} ` `} ` ` `  `// This code is contributed by AbhiThakur `

Output:

```Yes
```

Time Complexity: O(N)

Don’t stop now and take your learning to the next level. Learn all the important concepts of Data Structures and Algorithms with the help of the most trusted course: DSA Self Paced. Become industry ready at a student-friendly price.

My Personal Notes arrow_drop_up 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.