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# Php Program to Print a given matrix in reverse spiral form

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```

## 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``?>`

Output:

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

Time complexity: O(m*n) where m is number of rows and n is number of columns of a given matrix

Auxiliary space: O(1) as using constant variables

Please refer complete article on Print a given matrix in reverse spiral form for more details!

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