# Find kth smallest number in range [1, n] when all the odd numbers are deleted

Given two integers n and k, the task is to find the kth smallest element from the range [1, n] after deleting all the odd numbers from the range.

Examples:

Input: n = 8, k = 3
Output: 6
After deleting all the odd numbers from the range [1, 8]
2, 4, 6 and 8 are the only numbers left and 6 is the 3rd smallest.

Input: n = 8, k = 4
Output:

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

Approach: Since all odd numbers are removed so now only even numbers are left i.e. 2, 4, 6, 8, …..
Now, the kth smallest element will always be 2 * k.

Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach ` `#include ` `using` `namespace` `std; ` ` `  `// Function to return the kth smallest ` `// element from the range [1, n] after ` `// removing all the odd elements ` `int` `kthSmallest(``int` `n, ``int` `k) ` `{ ` `    ``return` `(2 * k); ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``int` `n = 8, k = 4; ` `    ``cout << kthSmallest(n, k); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java implementation of the approach ` `class` `GFG { ` ` `  `    ``// Function to return the kth smallest ` `    ``// element from the range [1, n] after ` `    ``// removing all the odd elements ` `    ``static` `int` `kthSmallest(``int` `n, ``int` `k) ` `    ``{ ` `        ``return` `(``2` `* k); ` `    ``} ` ` `  `    ``// Driver code ` `    ``public` `static` `void` `main(String args[]) ` `    ``{ ` `        ``int` `n = ``8``, k = ``4``; ` `        ``System.out.print(kthSmallest(n, k)); ` `    ``} ` `} `

## Python3

 `# Python3 implementation of the approach  ` ` `  `# Function to return the kth smallest  ` `# element from the range [1, n] after  ` `# removing all the odd elements  ` `def` `kthSmallest(n, k): ` `    ``return` `2` `*` `k ` ` `  `# Driver code ` `n ``=` `8``; k ``=` `4` `print``(kthSmallest(n, k)) ` ` `  `# This code is contributed  ` `# by Shrikant13 `

## C#

 `// C# implementation of the approach ` `using` `System; ` `class` `GFG { ` ` `  `    ``// Function to return the kth smallest ` `    ``// element from the range [1, n] after ` `    ``// removing all the odd elements ` `    ``static` `int` `kthSmallest(``int` `n, ``int` `k) ` `    ``{ ` `        ``return` `(2 * k); ` `    ``} ` ` `  `    ``// Driver code ` `    ``public` `static` `void` `Main() ` `    ``{ ` `        ``int` `n = 8, k = 4; ` `        ``Console.WriteLine(kthSmallest(n, k)); ` `    ``} ` `} ` ` `  `// This code is contributed by Code_Mech `

## PHP

 ` `

Output:

```8
```

Time Complexity: O(1)

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Improved By : shrikanth13, Code_Mech