Merging elements of two different arrays alternatively in third array

Given two arrays arr1[] and arr2[], we need to combine two arrays in such a way that the combined array has alternate elements of both. If one array has extra element, then these elements are appended at the end of the combined array.

Input : arr1[] = {1, 2, 3, 4, 5, 6}
arr2[] = {11, 22, 33, 44}
Output: {1, 11, 2, 22, 3, 33, 4, 44, 5, 6}

Input : arr1[] = {1, 2, 3, 4, 5, 6, 7, 8}
arr2[] = {11, 22, 33, 44}
Output: {1, 11, 2, 22, 3, 33, 4, 44, 5, 6, 7, 8}

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

We traverse both given arrays and one by one put their elements into combined array. After one of the arrays is exhausted, we put remaining elements of other array.

C++

 // C++ program to merge two sorted arrays/ #include using namespace std;    // Alternatively merge arr1[0..n1-1] and arr2[0..n2-1] // into arr3[0..n1+n2-1] void alternateMerge(int arr1[], int arr2[], int n1,                     int n2, int arr3[]) {     int i = 0, j = 0, k = 0;        // Traverse both array     while (i

Java

 // Java program to merge two sorted arrays import java.io.*;    class GFG {            // Alternatively merge arr1[0..n1-1] and      // arr2[0..n2-1] into arr3[0..n1+n2-1]     static void alternateMerge(int arr1[], int arr2[],                                 int n1, int n2, int arr3[])     {         int i = 0, j = 0, k = 0;                // Traverse both array         while (i < n1 && j < n2)         {             arr3[k++] = arr1[i++];             arr3[k++] = arr2[j++];         }                // Store remaining elements of first array         while (i < n1)             arr3[k++] = arr1[i++];                // Store remaining elements of second array         while (j < n2)             arr3[k++] = arr2[j++];     }            // Driver code     public static void main(String args[])     {         int arr1[] = {1, 3, 5, 7, 9, 11};         int n1 = arr1.length;                int arr2[] = {2, 4, 6, 8};         int n2 = arr2.length;                int arr3[] = new int[n1+n2];         alternateMerge(arr1, arr2, n1, n2, arr3);                System.out.println("Array after merging");         for (int i = 0; i < n1 + n2; i++)             System.out.print( arr3[i] + " ");     } }    // This code is contributed  // by Nikita Tiwari.

Python3

 # Python3 program to merge two sorted arrays/    # Alternatively merge arr1[0..n1-1] and  # arr2[0..n2-1] into arr3[0..n1 + n2-1] def alternateMerge(arr1, arr2, n1, n2, arr3) :     i = 0; j = 0; k = 0        # Traverse both array     while (i < n1 and j < n2) :         arr3[k] = arr1[i]         i += 1         k += 1                    arr3[k] = arr2[j]         j += 1         k += 1               # Store remaining elements of first array     while (i < n1) :         arr3[k] = arr1[i]         i += 1         k += 1        # Store remaining elements of second array     while (j < n2) :         arr3[k] = arr2[j]         k += 1         j += 1                       # Driver code arr1 = [1, 3, 5, 7, 9, 11] n1 = len(arr1)    arr2 = [2, 4, 6, 8] n2 = len(arr2)    arr3=  *(n1 + n2) alternateMerge(arr1, arr2, n1, n2, arr3)    print("Array after merging") for i in range(0, (n1 + n2)) :     print(arr3[i] , end = " ")    # This code is contributed by Nikita Tiwari.

C#

 // C# program to merge two sorted arrays using System;    class GFG {            // Alternatively merge arr1[0..n1-1]     // and arr2[0..n2-1] into arr3[0..n1+n2-1]     static void alternateMerge(int []arr1, int []arr2,                            int n1, int n2, int []arr3)     {         int i = 0, j = 0, k = 0;                // Traverse both array         while (i < n1 && j < n2)         {             arr3[k++] = arr1[i++];             arr3[k++] = arr2[j++];         }                // Store remaining elements of first array         while (i < n1)             arr3[k++] = arr1[i++];                // Store remaining elements of second array         while (j < n2)             arr3[k++] = arr2[j++];     }            // Driver code     public static void Main()     {         int []arr1 = new int[]{1, 3, 5, 7, 9, 11};         int n1 = arr1.Length;            int []arr2 = new int[]{2, 4, 6, 8};         int n2 = arr2.Length;            int []arr3= new int[n1 + n2];         alternateMerge(arr1, arr2, n1, n2, arr3);            Console.WriteLine("Array after merging");         for (int i = 0; i < n1+n2; i++)             Console.Write(arr3[i] + " ");     }  }    // This code is contributed by Sam007.

PHP



Output :

Array after merging
1 2 3 4 5 6 7 8 9 11

Time Complexity : O(n1 + n2)

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