# Print a given matrix in reverse spiral form

• Difficulty Level : Medium
• Last Updated : 12 Jul, 2022

Given a 2D array, print it in reverse spiral form. We have already discussed Print a given matrix in spiral form. This article discusses how to do the reverse printing. See the following examples.

```Input:
1    2   3   4
5    6   7   8
9   10  11  12
13  14  15  16
Output:
10 11 7 6 5 9 13 14 15 16 12 8 4 3 2 1
Input:
1   2   3   4  5   6
7   8   9  10  11  12
13  14  15 16  17  18
Output:
11 10 9 8 7 13 14 15 16 17 18 12 6 5 4 3 2 1```

Implementation:

## C++

 `// This is a modified code of``// https://www.geeksforgeeks.org/print-a-given-matrix-in-spiral-form/``#include ``#define R 3``#define C 6``using` `namespace` `std;` `// Function that print matrix in reverse spiral form.``void` `ReversespiralPrint(``int` `m, ``int` `n, ``int` `a[R][C])``{``    ``// Large array to initialize it``    ``// with elements of matrix``    ``long` `int` `b;``    ` `    ``/* k - starting row index``    ``l - starting column index*/``    ``int` `i, k = 0, l = 0;``    ` `    ``// Counter for single dimension array``    ``//in which elements will be stored``    ``int` `z = 0;``    ` `    ``// Total elements in matrix``    ``int` `size = m*n;` `    ``while` `(k < m && l < n)``    ``{``        ``// Variable to store value of matrix.``        ``int` `val;``        ` `        ``/* Print the first row from the remaining rows */``        ``for` `(i = l; i < n; ++i)``        ``{``            ``// printf("%d ", a[k][i]);``            ``val = a[k][i];``            ``b[z] = val;``            ``++z;``        ``}``        ``k++;` `        ``/* Print the last column from the remaining columns */``        ``for` `(i = k; i < m; ++i)``        ``{``            ``// printf("%d ", a[i][n-1]);``            ``val = a[i][n-1];``            ``b[z] = val;``            ``++z;``        ``}``        ``n--;` `        ``/* Print the last row from the remaining rows */``        ``if` `( k < m)``        ``{``            ``for` `(i = n-1; i >= l; --i)``            ``{``                ``// printf("%d ", a[m-1][i]);``                ``val = a[m-1][i];``                ``b[z] = val;``                ``++z;``            ``}``            ``m--;``        ``}` `        ``/* Print the first column from the remaining columns */``        ``if` `(l < n)``        ``{``            ``for` `(i = m-1; i >= k; --i)``            ``{``                ``// printf("%d ", a[i][l]);``                ``val = a[i][l];``                ``b[z] = val;``                ``++z;``            ``}``            ``l++;``        ``}``    ``}``    ``for` `(``int` `i=size-1 ; i>=0 ; --i)``    ``{``        ``cout<

## Java

 `// JAVA Code for Print a given matrix in``// reverse spiral form``class` `GFG {` `    ``public` `static` `int` `R = ``3``, C = ``6``;``    ` `    ``// Function that print matrix in reverse spiral form.``    ``public` `static` `void` `ReversespiralPrint(``int` `m, ``int` `n,``                                             ``int` `a[][])``    ``{``        ``// Large array to initialize it``        ``// with elements of matrix``        ``long` `b[] = ``new` `long``[``100``];``         ` `        ``/* k - starting row index``        ``l - starting column index*/``        ``int` `i, k = ``0``, l = ``0``;``         ` `        ``// Counter for single dimension array``        ``//in which elements will be stored``        ``int` `z = ``0``;``         ` `        ``// Total elements in matrix``        ``int` `size = m * n;``     ` `        ``while` `(k < m && l < n)``        ``{``            ``// Variable to store value of matrix.``            ``int` `val;``             ` `            ``/* Print the first row from the remaining``            ``rows */``            ``for` `(i = l; i < n; ++i)``            ``{``                ` `                ``val = a[k][i];``                ``b[z] = val;``                ``++z;``            ``}``            ``k++;``     ` `            ``/* Print the last column from the remaining``            ``columns */``            ``for` `(i = k; i < m; ++i)``            ``{``                ` `                ``val = a[i][n-``1``];``                ``b[z] = val;``                ``++z;``            ``}``            ``n--;``     ` `            ``/* Print the last row from the remaining``            ``rows */``            ``if` `( k < m)``            ``{``                ``for` `(i = n-``1``; i >= l; --i)``                ``{``                    ` `                    ``val = a[m-``1``][i];``                    ``b[z] = val;``                    ``++z;``                ``}``                ``m--;``            ``}``     ` `            ``/* Print the first column from the remaining``            ``columns */``            ``if` `(l < n)``            ``{``                ``for` `(i = m-``1``; i >= k; --i)``                ``{``                    ` `                    ``val = a[i][l];``                    ``b[z] = val;``                    ``++z;``                ``}``                ``l++;``            ``}``        ``}``        ` `        ``for` `(``int` `x = size-``1` `; x>=``0` `; --x)``        ``{``            ``System.out.print(b[x]+``" "``);``        ``}``    ``}   ``    ` `    ``/* Driver program to test above function */``    ``public` `static` `void` `main(String[] args)``    ``{``        ``int` `a[][] = { {``1``, ``2``, ``3``, ``4``, ``5``, ``6``},``                    ``{``7``, ``8``, ``9``, ``10``, ``11``, ``12``},``                    ``{``13``, ``14``, ``15``, ``16``, ``17``, ``18``}};``        ` `        ``ReversespiralPrint(R, C, a);``       ` `    ``}``  ``}``// This code is contributed by Arnav Kr. Mandal.`

## Python3

 `# Python3 Code to Print a given ``# matrix in reverse spiral form` `# This is a modified code of``# https:#www.geeksforgeeks.org/print-a-given-matrix-in-spiral-form/``R, C ``=` `3``, ``6` `def` `ReversespiralPrint(m, n, a):` `    ``# Large array to initialize it``    ``# with elements of matrix``    ``b ``=` `[``0` `for` `i ``in` `range``(``100``)]` `    ``#/* k - starting row index``    ``#l - starting column index*/``    ``i, k, l ``=` `0``, ``0``, ``0` `    ``# Counter for single dimension array``    ``# in which elements will be stored``    ``z ``=` `0` `    ``# Total elements in matrix``    ``size ``=` `m ``*` `n` `    ``while` `(k < m ``and` `l < n):``        ` `        ``# Variable to store value of matrix.``        ``val ``=` `0` `        ``# Print the first row``        ``# from the remaining rows``        ``for` `i ``in` `range``(l, n):``            ` `            ``# printf("%d ", a[k][i])``            ``val ``=` `a[k][i]``            ``b[z] ``=` `val``            ``z ``+``=` `1``        ``k ``+``=` `1` `        ``# Print the last column``        ``# from the remaining columns``        ``for` `i ``in` `range``(k, m):` `            ``# printf("%d ", a[i][n-1])``            ``val ``=` `a[i][n ``-` `1``]``            ``b[z] ``=` `val``            ``z ``+``=` `1` `        ``n ``-``=` `1` `        ``# Print the last row``        ``# from the remaining rows``        ``if` `(k < m):``            ``for` `i ``in` `range``(n ``-` `1``, l ``-` `1``, ``-``1``):``                ` `                ``# printf("%d ", a[m-1][i])``                ``val ``=` `a[m ``-` `1``][i]``                ``b[z] ``=` `val``                ``z ``+``=` `1` `        ``m ``-``=` `1` `        ``# Print the first column``        ``# from the remaining columns``        ``if` `(l < n):``            ``for` `i ``in` `range``(m ``-` `1``, k ``-` `1``, ``-``1``):``                ` `                ``# printf("%d ", a[i][l])``                ``val ``=` `a[i][l]``                ``b[z] ``=` `val``                ``z ``+``=` `1``            ``l ``+``=` `1` `    ``for` `i ``in` `range``(size ``-` `1``, ``-``1``, ``-``1``):``        ``print``(b[i], end ``=` `" "``)` `# Driver Code``a ``=` `[[``1``, ``2``, ``3``, ``4``, ``5``, ``6``],``     ``[``7``, ``8``, ``9``, ``10``, ``11``, ``12``],``     ``[``13``, ``14``, ``15``, ``16``, ``17``, ``18``]]` `ReversespiralPrint(R, C, a)` `# This code is contributed by mohit kumar`

## C#

 `// C# Code for Print a given matrix in``// reverse spiral form``using` `System;``class` `GFG {` `    ``public` `static` `int` `R = 3, C = 6;``    ` `    ``// Function that print matrix in reverse spiral form.``    ``public` `static` `void` `ReversespiralPrint(``int` `m, ``int` `n,``                                            ``int` `[,]a)``    ``{``        ``// Large array to initialize it``        ``// with elements of matrix``        ``long` `[]b = ``new` `long``;``        ` `        ``/* k - starting row index``        ``l - starting column index*/``        ``int` `i, k = 0, l = 0;``        ` `        ``// Counter for single dimension array``        ``//in which elements will be stored``        ``int` `z = 0;``        ` `        ``// Total elements in matrix``        ``int` `size = m * n;``    ` `        ``while` `(k < m && l < n)``        ``{``            ``// Variable to store value of matrix.``            ``int` `val;``            ` `            ``/* Print the first row from the remaining``            ``rows */``            ``for` `(i = l; i < n; ++i)``            ``{``                ` `                ``val = a[k,i];``                ``b[z] = val;``                ``++z;``            ``}``            ``k++;``    ` `            ``/* Print the last column from the remaining``            ``columns */``            ``for` `(i = k; i < m; ++i)``            ``{``                ` `                ``val = a[i,n-1];``                ``b[z] = val;``                ``++z;``            ``}``            ``n--;``    ` `            ``/* Print the last row from the remaining``            ``rows */``            ``if` `( k < m)``            ``{``                ``for` `(i = n-1; i >= l; --i)``                ``{``                    ` `                    ``val = a[m-1,i];``                    ``b[z] = val;``                    ``++z;``                ``}``                ``m--;``            ``}``    ` `            ``/* Print the first column from the remaining``            ``columns */``            ``if` `(l < n)``            ``{``                ``for` `(i = m-1; i >= k; --i)``                ``{``                    ` `                    ``val = a[i,l];``                    ``b[z] = val;``                    ``++z;``                ``}``                ``l++;``            ``}``        ``}``        ` `        ``for` `(``int` `x = size-1 ; x>=0 ; --x)``        ``{``        ``Console.Write(b[x]+``" "``);``        ``}``    ``}``    ` `    ``/* Driver program to test above function */``    ``public` `static` `void` `Main()``    ``{``        ``int` `[ ,]a = { {1, 2, 3, 4, 5, 6},``                    ``{7, 8, 9, 10, 11, 12},``                    ``{13, 14, 15, 16, 17, 18}};``        ` `        ``ReversespiralPrint(R, C, a);``        ` `    ``}``}``// This code is contributed by vt_m.`

## PHP

 `= ``\$l``; --``\$i``)``            ``{``                ` `                ``// printf("%d ", a[m-1][i]);``                ``\$val` `= ``\$a``[``\$m``-1][``\$i``];``                ``\$b``[``\$z``] = ``\$val``;``                ``++``\$z``;``            ``}``            ``\$m``--;``        ``}` `        ``// Print the first column``        ``// from the remaining columns``        ``if` `(``\$l` `< ``\$n``)``        ``{``            ``for` `(``\$i` `= ``\$m` `- 1; ``\$i` `>= ``\$k``; --``\$i``)``            ``{``                ``\$val` `= ``\$a``[``\$i``][``\$l``];``                ``\$b``[``\$z``] = ``\$val``;``                ``++``\$z``;``            ``}``            ``\$l``++;``        ``}``    ``}``    ``for` `(``\$i` `= ``\$size` `- 1; ``\$i` `>= 0; --``\$i``)``    ``{``        ``echo` `\$b``[``\$i``].``" "``;``    ``}``}` `    ``// Driver Code``    ``\$a``= ``array``(``array``(1, 2, 3, 4, 5, 6),``              ``array``(7, 8, 9, 10, 11, 12),``              ``array``(13, 14, 15, 16, 17, 18));``    ``ReversespiralPrint(``\$R``, ``\$C``, ``\$a``);` `// This Code is contributed by mits``?>`

## Javascript

 ``

Output

`11 10 9 8 7 13 14 15 16 17 18 12 6 5 4 3 2 1 `

Time Complexity: O(m*n), To traverse the matrix O(m*n) time is required.
Auxiliary Space: O(1), No extra space is required.

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

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