Construct a linked list from 2D matrix

Given a matrix. Convert it into a linked list matrix such that each node is connected to its next right and down node.

Example:

Input : 2D matrix 
1 2 3
4 5 6
7 8 9

Output :
1 -> 2 -> 3 -> NULL
|    |    |
v    v    v
4 -> 5 -> 6 -> NULL
|    |    |
v    v    v
7 -> 8 -> 9 -> NULL
|    |    |
v    v    v
NULL NULL NULL

Question Source : Factset Interview Experience | Set 9

The idea is to construct a new node for every element of matrix and recursively create its down and right nodes.

C++

filter_none

edit
close

play_arrow

link
brightness_4
code

// CPP program to construct a linked list
// from given 2D matrix
#include <bits/stdc++.h>
using namespace std;
  
// struct node of linked list
struct Node {
    int data;
    Node* right, *down;
};
  
// returns head pointer of linked list
// constructed from 2D matrix
Node* construct(int arr[][3], int i, int j, 
                              int m, int n)
{
    // return if i or j is out of bounds
    if (i > n - 1 || j > m - 1)
        return NULL;
  
    // create a new node for current i and j
    // and recursively allocate its down and
    // right pointers
    Node* temp = new Node();
    temp->data = arr[i][j];
    temp->right = construct(arr, i, j + 1, m, n);
    temp->down  = construct(arr, i + 1, j, m, n);
    return temp;
}
  
// utility function for displaying
// linked list data
void display(Node* head)
{
    // pointer to move right
    Node* Rp;
  
    // pointer to move down
    Node* Dp = head;
  
    // loop till node->down is not NULL
    while (Dp) {
        Rp = Dp;
  
        // loop till node->right is not NULL
        while (Rp) {
            cout << Rp->data << " ";
            Rp = Rp->right;
        }
        cout << "\n";
        Dp = Dp->down;
    }
}
  
// driver program
int main()
{
    // 2D matrix
    int arr[][3] = {
        { 1, 2, 3 },
        { 4, 5, 6 },
        { 7, 8, 9 }
    };
  
    int m = 3, n = 3;
    Node* head = construct(arr, 0, 0, m, n);
    display(head);
    return 0;
}

chevron_right






                        filter_none









Java














                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















// Java program to construct a linked list 


// from given 2D matrix 


public class Linked_list_2D_Matrix { 


  


    // node of linked list 


    static class Node { 


        int data; 


        Node right; 


        Node down; 


    }; 


  


    // returns head pointer of linked list 


    // constructed from 2D matrix 


    static Node construct(int arr[][], int i, int j,  


                                     int m, int n) { 


          


        // return if i or j is out of bounds 


        if (i > n - 1 || j > m - 1) 


            return null; 


  


        // create a new node for current i and j 


        // and recursively allocate its down and 


        // right pointers 


        Node temp = new Node(); 


        temp.data = arr[i][j]; 


        temp.right = construct(arr, i, j + 1, m, n); 


        temp.down = construct(arr, i + 1, j, m, n); 


        return temp; 


    } 


  


    // utility function for displaying 


    // linked list data 


    static void display(Node head) { 


          


        // pointer to move right 


        Node Rp; 


  


        // pointer to move down 


        Node Dp = head; 


  


        // loop till node->down is not NULL 


        while (Dp != null) { 


            Rp = Dp; 


  


            // loop till node->right is not NULL 


            while (Rp != null) { 


                System.out.print(Rp.data + " "); 


                Rp = Rp.right; 


            } 


            System.out.println(); 


            Dp = Dp.down; 


        } 


    } 


  


    // driver program 


    public static void main(String args[]) { 


        // 2D matrix 


        int arr[][] = { { 1, 2, 3 },  


                        { 4, 5, 6 },  


                       { 7, 8, 9 } }; 


  


        int m = 3, n = 3; 


        Node head = construct(arr, 0, 0, m, n); 


        display(head); 


    } 


  


} 


// This code is contributed by Sumit Ghosh 



















                        chevron_right







                        filter_none









C#














                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















// C# program to construct a linked list 


// from given 2D matrix 


using System; 


      


public class Linked_list_2D_Matrix 


{ 


  


    // node of linked list 


    public class Node  


    { 


        public int data; 


        public Node right; 


        public Node down; 


    }; 


  


    // returns head pointer of linked list 


    // constructed from 2D matrix 


    static Node construct(int [,]arr, int i, int j,  


                                    int m, int n)  


    { 


          


        // return if i or j is out of bounds 


        if (i > n - 1 || j > m - 1) 


            return null; 


  


        // create a new node for current i and j 


        // and recursively allocate its down and 


        // right pointers 


        Node temp = new Node(); 


        temp.data = arr[i, j]; 


        temp.right = construct(arr, i, j + 1, m, n); 


        temp.down = construct(arr, i + 1, j, m, n); 


        return temp; 


    } 


  


    // utility function for displaying 


    // linked list data 


    static void display(Node head) 


    { 


          


        // pointer to move right 


        Node Rp; 


  


        // pointer to move down 


        Node Dp = head; 


  


        // loop till node->down is not NULL 


        while (Dp != null)  


        { 


            Rp = Dp; 


  


            // loop till node->right is not NULL 


            while (Rp != null)  


            { 


                Console.Write(Rp.data + " "); 


                Rp = Rp.right; 


            } 


            Console.WriteLine(); 


            Dp = Dp.down; 


        } 


    } 


  


    // Driver program 


    public static void Main()  


    { 


        // 2D matrix 


        int [,]arr = { { 1, 2, 3 },  


                        { 4, 5, 6 },  


                    { 7, 8, 9 } }; 


  


        int m = 3, n = 3; 


        Node head = construct(arr, 0, 0, m, n); 


        display(head); 


    } 


} 


  


/* This code contributed by PrinciRaj1992 */



















                        chevron_right







                        filter_none










Output:


1 2 3 
4 5 6 
7 8 9



This article is contributed by Mandeep Singh. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.


Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.



          
          
          
          

            

    

        My Personal Notes
        arrow_drop_up
    

    

        
        

            
            
        

    


Recommended Posts:

Improved By :  princiraj1992