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Program to concatenate two given Matrices of same size

  • Last Updated : 12 Apr, 2021

Given two matrices A and B of size M x N, the task is to concatenate them into one matrix.
Concatenation of matrix: The process of appending elements of every row of the matrix one after the other is known as the Concatenation of matrix. 
Examples: 

Input:
A[][] = {{1, 2}, 
         {3, 4}},
B[][] = {{5, 6}, 
         {7, 8}}
Output: 
1 2 5 6
3 4 7 8
Explanation:
Elements of every row of the matrix B 
is appended into the row of matrix A.

Input: 
A[][] = {{2, 4}, 
         {3, 4}}
B[][] = {{1, 2}, 
         {1, 3}}       
Output: 
2 4 1 2 
3 4 1 3

Approach: The idea is to declare a matrix of size N x 2*M, then traverse over matrix A and store the elements in the first half of the matrix and then similarly iterate over matrix B and store the elements in another half of the matrix with the help of the below formulae: 

// For filling the
// first half of matrix
matrix[i][j] = A[i][j]

// For filling the
// second half of matrix
matrix[i][j+N] = A[i][j + N]

Below is the implementation of the above approach: 

C++




// C++ implementation to concatenate
// two matrices of size N x M
 
#include <bits/stdc++.h>
 
using namespace std;
 
#define M 2
#define N 2
 
// Function to concatenate two
// matrices A[][] and B[][]
void mergeMatrix(int A[M][N],
                 int B[M][N])
{
 
    // Matrix to store
    // the result
    int C[M][2 * N];
 
    // Merge the two matrices
    for (int i = 0; i < M; i++) {
        for (int j = 0; j < N; j++) {
 
            // To store elements
            // of matrix A
            C[i][j] = A[i][j];
 
            // To store elements
            // of matrix B
            C[i][j + N] = B[i][j];
        }
    }
 
    // Print the result
    for (int i = 0; i < M; i++) {
        for (int j = 0; j < 2 * N;
             j++)
            cout << C[i][j] << " ";
        cout << endl;
    }
}
 
// Driven Code
int main()
{
    int A[M][N] = { { 1, 2 },
                    { 3, 4 } };
 
    int B[M][N] = { { 5, 6 },
                    { 7, 8 } };
 
    // Find the merge of
    // the 2 matrices
    mergeMatrix(A, B);
 
    return 0;
}

Java




// Java implementation to concatenate
// two matrices of size N x M
class GFG{
 
static final int M = 2;
static final int N = 2;
 
// Function to concatenate two
// matrices A[][] and B[][]
static void mergeMatrix(int A[][],
                        int B[][])
{
 
    // Matrix to store
    // the result
    int [][]C = new int[M][2 * N];
 
    // Merge the two matrices
    for(int i = 0; i < M; i++)
    {
       for(int j = 0; j < N; j++)
       {
          // To store elements
          // of matrix A
          C[i][j] = A[i][j];
           
          // To store elements
          // of matrix B
          C[i][j + N] = B[i][j];
            
       }
    }
 
    // Print the result
    for(int i = 0; i < M; i++)
    {
       for(int j = 0; j < 2 * N; j++)
          System.out.print(C[i][j] + " ");
 
       System.out.println();
    }
}
 
// Driven Code
public static void main(String[] args)
{
    int A[][] = { { 1, 2 },
                  { 3, 4 } };
 
    int B[][] = { { 5, 6 },
                  { 7, 8 } };
 
    // Find the merge of
    // the 2 matrices
    mergeMatrix(A, B);
}
}
 
// This code is contributed by gauravrajput1

Python3




# Python3 implementation to concatenate
# two matrices of size N x M
 
M = 2
N = 2
 
# Function to concatenate two
# matrices A[][] and B[][]
def mergeMatrix(A, B):
 
    # Matrix to store
    # the result
    C = [[0 for j in range(2 * N)]
            for i in range(M)]
     
    # Merge the two matrices
    for i in range(M):
        for j in range(N):
             
            # To store elements
            # of matrix A
            C[i][j] = A[i][j]
             
            # To store elements
            # of matrix B
            C[i][j + N] = B[i][j]
     
    # Print the result
    for i in range(M):
        for j in range(2 * N):    
            print(C[i][j], end = ' ')
             
        print()
 
# Driver code
if __name__=='__main__':
     
    A = [ [1, 2], [3, 4] ]
    B = [ [5, 6], [7, 8] ]
     
    # Find the merge of
    # the 2 matrices
    mergeMatrix(A, B)
 
# This code is contributed by rutvik_56

C#




// C# implementation to concatenate
// two matrices of size N x M
using System;
 
class GFG{
     
const int M = 2;
const int N = 2;
     
// Function to concatenate two
// matrices A[][] and B[][]
static void mergeMatrix(int[,] A, int[,] B)
{
     
    // Matrix to store
    // the result
    int[,] C = new int[M, 2 * N];
     
    // Merge the two matrices
    for(int i = 0; i < M; i++)
    {
       for(int j = 0; j < N; j++)
       {
            
          // To store elements
          // of matrix A
          C[i, j] = A[i, j];
           
          // To store elements
          // of matrix B
          C[i, j + N] = B[i, j];
       }
    }
     
    // Print the result
    for(int i = 0; i < M; i++)
    {
       for(int j = 0; j < 2 * N; j++)
          Console.Write(C[i, j] + " ");
     
       Console.WriteLine();
    }
}
 
// Driver code
static void Main()
{
    int[,] A = { { 1, 2 },
                 { 3, 4 } };
 
    int[,] B = { { 5, 6 },
                 { 7, 8 } };
     
    // Find the merge of
    // the 2 matrices
    mergeMatrix(A, B);
}
}
 
// This code is contributed by divyeshrabadiya07

Javascript




<script>
// Javascript implementation to concatenate
// two matrices of size N x M
M = 2
N = 2
 
// Function to concatenate two
// matrices A[][] and B[][]
function mergeMatrix(A,B)
{
 
    // Matrix to store
    // the result
    var C = [[0,0,0,0], [0,0,0,0]]
 
    // Merge the two matrices
    for (var i = 0; i < M; i++)
    {
        for (var j = 0; j < N; j++)
        {
 
            // To store elements
            // of matrix A
            C[i][j] = A[i][j];
 
            // To store elements
            // of matrix B
            C[i][j + N] = B[i][j];
        }
    }
 
    // Print the result
    for (var i = 0; i < M; i++)
    {
        for (var j = 0; j < 2 * N;
             j++)
            document.write( C[i][j] + " ");
        document.write("<br>");
    }
}
 
// Driven Code
var A = [ [ 1, 2 ],
                [ 3, 4 ] ];
var B = [ [ 5, 6 ],
                [ 7, 8 ] ];
                 
// Find the merge of
// the 2 matrices
mergeMatrix(A, B);
 
// This code is contributed by noob2000.
</script>
Output: 
1 2 5 6 
3 4 7 8

 

Time Complexity: O(M * N)

Auxiliary Space: O(M * N)

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