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Enlarge a Matrix such that each element occurs in R rows and C columns
  • Last Updated : 09 Oct, 2020

Given a matrix arr[][] of size N x M, and two numbers R and C, the task is to enlarge this matrix such that each element of the original matrix occurs in R rows and C columns in the enlarged matrix.

Examples: 

Input: arr[][] = {{1, 2, 3}, {4, 5, 6}} R = 3, C = 2 
Output: 
1 1 2 2 3 3 4 4 5 5 6 6 
1 1 2 2 3 3 4 4 5 5 6 6 
1 1 2 2 3 3 4 4 5 5 6 6 
Explanation: 
Every element of the original matrix appears in 3 rows and 2 columns in the enlarged matrix.

Input: arr = {{1, 2}}, R = 2, C = 3 
Output: 
1 1 1 2 2 2 
1 1 1 2 2 2 
Explanation: 
Each element of the original matrix appears in 2 rows and 3 columns in the enlarged matrix. 

Approach: This problem can be solved by keeping either the number of rows or columns fixed. In this article, the number of rows is fixed. Therefore, for any matrix of dimension N x M, the number of rows in the final answer would be R. 
The idea is to first convert the given matrix into a one dimensional array (i.e) flatten the given matrix. Now, for every element in the flattened matrix, append the values in R rows and C columns of the final enlarged matrix. 



Below is the implementation of the above approach:  

C++

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// C++ program to enlarge a matrix
// such that each element occurs in
// R rows and C columns
#include <bits/stdc++.h>
using namespace std;
 
// Function to convert the matrix
// into a 1-D array
vector<int> oneD(vector<vector<int>> &matrix){
      
    // Variable to store the
    // given matrix
    vector<int> m;
  
    // Iterating through all the
    // elements of the matrix
    for(int i = 0; i < matrix.size(); ++i)
        for(int j = 0; j < matrix[0].size(); ++j)
            // Adding the element into the
            // defined matrix
            m.push_back(matrix[i][j]);
  
    return m;
}
  
// Function to enlarge a matrix
// such that each element occurs
// in R rows and C columns
vector<vector<int>> dimensions(int R, int C, vector<int> matrix) {
      
    // Initializing the enlarged
    // matrix
    vector<vector<int>> ans(R+1);
 
    // Variables to iterate over
    // the matrix
    int ctr = 0;
    int r = 0;
      
    while(ctr < matrix.size()) {
  
        // To keep the rows in the
        // range [0, R]
        r = r % R;
        int c = 0;
        while(c < C) {            
            // In order to fix the number
            // of columns, the above r
            // statement can be commented 
            // and this can be uncommented
            // c = c % C
               for(int i = 0; i < R; ++i)
                   ans[i].push_back(matrix[ctr]);
                
               c += 1;
          }
        ctr += 1;
        r += 1;
    }
 
    return ans;
}
     
// Driver code
int main() {
 
    vector<vector<int>> arr = {{1, 2}, {3, 4}};
    int R = 2, C = 3;
  
    vector<vector<int>> ans = dimensions(R, C, oneD(arr));
      
    // Print the enlarged matrix
    for(int i = 0; i < ans.size(); ++i) {
     
        for(int j = 0; j < ans[i].size(); ++j) {
            cout << ans[i][j] << " ";
        }
     
        cout<<endl;
    }
 
    return 0;
}
 
// This code is contributed by Sanjit_Prasad

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Java

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// Java program to enlarge a matrix
// such that each element occurs in
// R rows and C columns
import java.io.*;
import java.util.*;
 
class GFG{
 
// Function to convert the matrix
// into a 1-D array
static ArrayList<Integer>oneD(
    ArrayList<ArrayList<Integer>> matrix)
{
     
    // Variable to store the
    // given matrix
    ArrayList<Integer> m = new ArrayList<Integer>();
 
    // Iterating through all the
    // elements of the matrix
    for(int i = 0; i < matrix.size(); ++i)
        for(int j = 0; j < matrix.get(0).size(); ++j)
         
            // Adding the element into the
            // defined matrix
            m.add(matrix.get(i).get(j));
 
    return m;
}
 
// Function to enlarge a matrix
// such that each element occurs
// in R rows and C columns
static ArrayList<ArrayList<Integer>>dimensions(
    int R, int C, ArrayList<Integer> matrix)
{
     
    // Initializing the enlarged
    // matrix
    ArrayList<ArrayList<Integer>> ans = new ArrayList<>();
    for(int i = 0; i < R; ++i)
    {
        ans.add(new ArrayList<Integer>());
    }
 
    // Variables to iterate over
    // the matrix
    int ctr = 0;
    int r = 0;
 
    while (ctr < matrix.size())
    {
         
        // To keep the rows in the
        // range [0, R]
        r = r % R;
        int c = 0;
         
        while (c < C)
        {
             
            // In order to fix the number
            // of columns, the above r
            // statement can be commented
            // and this can be uncommented
            // c = c % C
            for(int i = 0; i < R; ++i)
            {
                ans.get(i).add(matrix.get(ctr));
            }
            c += 1;
        }
        ctr += 1;
        r += 1;
    }
    return ans;
}
 
// Driver code
public static void main(String[] args)
{
 
    ArrayList<ArrayList<Integer>> arr = new ArrayList<>();
    arr.add(new ArrayList<Integer>(Arrays.asList(1, 2)));
    arr.add(new ArrayList<Integer>(Arrays.asList(3, 4)));
    int R = 2, C = 3;
 
    ArrayList<ArrayList<Integer>> ans = new ArrayList<>(
        dimensions(R, C, oneD(arr)));
 
    // Print the enlarged matrix
    for(int i = 0; i < ans.size(); ++i)
    {
        System.out.print("[");
        for(int j = 0; j < ans.get(i).size(); ++j)
        {
            System.out.print(ans.get(i).get(j) + ", ");
        }
        System.out.print("]\n");
    }
}
}
 
// This code is contributed by akhilsaini

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Python3

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# Python program to enlarge a matrix
# such that each element occurs in
# R rows and C columns
 
# Function to convert the matrix
# into a 1-D array
def oneD(matrix):
     
    # Variable to store the
    # given matrix
    m = []
 
    # Iterating through all the
    # elements of the matrix
    for i in range(len(matrix)):
        for j in range(len(matrix[0])):
 
            # Adding the element into the
            # defined matrix
            m.append(matrix[i][j])
 
    return m[:]
 
# Function to enlarge a matrix
# such that each element occurs
# in R rows and C columns
def dimensions(R, C, matrix):
     
    # Initializing the enlarged
    # matrix
    ans = [[]] * R
     
    # Variables to iterate over
    # the matrix
    ctr = 0
    r = 0
 
     
    while(ctr < len(matrix)):
 
        # To keep the rows in the
        # range [0, R]
        r = r % R
        c = 0
        while(c < C):
             
            # In order to fix the number
            # of columns, the above r
            # statement can be commented 
            # and this can be uncommented
            # c = c % C
            ans[r].append(matrix[ctr])
             
            c+= 1
      
        ctr += 1
        r+= 1
         
         
    return ans
 
# Driver code
if __name__ == '__main__':
 
    arr = [[1, 2], [3, 4]]
    R, C = 2, 3
 
    ans = dimensions(R, C, oneD(arr))
     
    # Print the enlarged matrix
    for i in ans:
        print(i)

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C#

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// C# program to enlarge a matrix
// such that each element occurs in
// R rows and C columns
using System;
using System.Collections;
using System.Collections.Generic;
 
class GFG{
 
// Function to convert the matrix
// into a 1-D array
static List<int> oneD(List<List<int> > matrix)
{
     
    // Variable to store the
    // given matrix
    List<int> m = new List<int>();
 
    // Iterating through all the
    // elements of the matrix
    for(int i = 0; i < matrix.Count; ++i)
        for(int j = 0; j < matrix[0].Count; ++j)
         
            // Adding the element into the
            // defined matrix
            m.Add(matrix[i][j]);
 
    return m;
}
 
// Function to enlarge a matrix
// such that each element occurs
// in R rows and C columns
static List<List<int>> dimensions(int R, int C,
                                  List<int> matrix)
{
     
    // Initializing the enlarged
    // matrix
    List<List<int> > ans = new List<List<int> >();
    for(int i = 0; i < R; ++i)
    {
        ans.Add(new List<int>());
    }
 
    // Variables to iterate over
    // the matrix
    int ctr = 0;
    int r = 0;
 
    while (ctr < matrix.Count)
    {
         
        // To keep the rows in the
        // range [0, R]
        r = r % R;
        int c = 0;
         
        while (c < C)
        {
             
            // In order to fix the number
            // of columns, the above r
            // statement can be commented
            // and this can be uncommented
            // c = c % C
            for(int i = 0; i < R; ++i)
            {
                ans[i].Add(matrix[ctr]);
            }
            c += 1;
        }
        ctr += 1;
        r += 1;
    }
    return ans;
}
 
// Driver code
public static void Main()
{
 
    List<List<int>> arr = new List<List<int>>();
    arr.Add(new List<int>() { 1, 2 });
    arr.Add(new List<int>() { 3, 4 });
    int R = 2, C = 3;
 
    List<List<int>> ans = new List<List<int>>(
        dimensions(R, C, oneD(arr)));
 
    // Print the enlarged matrix
    for(int i = 0; i < ans.Count; ++i)
    {
        Console.Write("[");
        for(int j = 0; j < ans[i].Count; ++j)
        {
            Console.Write(ans[i][j] + ", ");
        }
        Console.Write("]\n");
    }
}
}
 
// This code is contributed by akhilsaini

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Output: 

[1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4]
[1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4]


 

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