Create an array such that XOR of subarrays of length K is X

Given three integers N, K and X, the task is to construct an array of length N, in which XOR of all elements of each contiguous sub-array of length K is X.
Examples: 
 

Input: N = 5, K = 1, X = 4 
Output: 4 4 4 4 4 
Explanation: 
Each subarray of length 1 has Xor value equal to 4.
Input: N = 5, K = 2, X = 4 
Output: 4 0 4 0 4 
Explanation: 
Each subarray of length 2 has Xor value equal to 4. 
 

Approach: 
To solve the problem mentioned above, we need to follow the steps given below:
 

• Bitwise-XOR of any number, X with 0 is equal to the number itself. So, if we set the first element of the array A as X, and the next K - 1 elements as 0, then we will have the XOR of elements of first sub-array of length K, equal to X.
• If we set A[K] as A[0], then we will have XOR(A[1], ..., A[K]) = X. Similarly, if we set A[K + 1] as A[1], then we will have XOR(A[2], ..., A[K+1]) = X
• Continuing in this manner, we can observe that the general formula can be described as below:

Below is the implementation of the above approach:
 

// C++ implementation to Create an array
// in which the XOR of all elements of
// each contiguous sub-array of
// length K is X

#include <bits/stdc++.h>
using namespace std;

// Function to construct the array
void constructArray(int N, int K, int X)
{

    // Creating a vector of size K,
    // initialised with 0
    vector<int> ans(K, 0);

    // Initialising the first element
    // with the given XOR
    ans[0] = X;

    for (int i = 0; i < N; ++i) {
        cout << ans[i % K] << " ";
    }

    cout << endl;
}

// Driver code
int main()
{
    int N = 5, K = 2, X = 4;

    constructArray(N, K, X);

    return 0;
}

// Java implementation to create an array 
// in which the XOR of all elements of 
// each contiguous sub-array of 
// length K is X 
class GFG{
    
// Function to construct the array 
public static void constructArray(int N, int K,
                                         int X) 
{ 
    
    // Creating an array of size K, 
    // initialised with 0 
    int[] ans = new int[K];
     
    // Initialising the first element 
    // with the given XOR 
    ans[0] = X; 
    
    for(int i = 0; i < N; ++i)
    {
       System.out.print(ans[i % K] + " ");
    } 
} 

// Driver code
public static void main(String[] args)
{
    int N = 5, K = 2, X = 4; 
    
    constructArray(N, K, X); 
}
}

// This code is contributed by divyeshrabadiya07

# Python3 implementation to create an array 
# in which the XOR of all elements of 
# each contiguous sub-array of 
# length K is X 

# Function to construct the array 
def constructArray(N, K, X):
    
    # Creating a list of size K, 
    # initialised with 0 
    ans = []
    
    for i in range(0, K):
        ans.append(0)
        
    # Initialising the first element 
    # with the given XOR 
    ans[0] = X
        
    for i in range(0, N):
        print(ans[i % K], end = " ")

# Driver code 
N = 5
K = 2
X = 4

# Function call
constructArray(N, K, X)

# This code is contributed by ishayadav181

// C# implementation to create an array 
// in which the XOR of all elements of 
// each contiguous sub-array of 
// length K is X 
using System;

class GFG{
    
// Function to construct the array 
public static void constructArray(int N, int K,
                                         int X) 
{ 
    
    // Creating an array of size K, 
    // initialised with 0 
    int[] ans = new int[K];
    
    // Initialising the first element 
    // with the given XOR 
    ans[0] = X; 
    
    for(int i = 0; i < N; ++i)
    {
        Console.Write(ans[i % K] + " ");
    } 
} 

// Driver code
public static void Main(string[] args)
{
    int N = 5, K = 2, X = 4; 
    
    constructArray(N, K, X); 
}
}

// This code is contributed by rutvik_56

<script>

// Javascript implementation to Create an array
// in which the XOR of all elements of
// each contiguous sub-array of
// length K is X

// Function to construct the array
function constructArray(N, K, X)
{

    // Creating a vector of size K,
    // initialised with 0
    let ans = new Array(K).fill(0);

    // Initialising the first element
    // with the given XOR
    ans[0] = X;

    for (let i = 0; i < N; ++i) {
        document.write(ans[i % K] + " ");
    }

    document.write("<br>");
}

// Driver code
    let N = 5, K = 2, X = 4;

    constructArray(N, K, X);

</script>

4 0 4 0 4

Time Complexity: O(N)
Auxiliary Space: O(K)