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# Traverse matrix in L shape

• Difficulty Level : Easy
• Last Updated : 04 May, 2021

Given a N * M matrix. The task is to traverse the given matrix in L shape as shown in below image. Attention reader! All those who say programming isn't for kids, just haven't met the right mentors yet. Join the  Demo Class for First Step to Coding Coursespecifically designed for students of class 8 to 12.

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Examples:

```Input : n = 3, m = 3
a[][] = { { 1, 2, 3 },
{ 4, 5, 6 },
{ 7, 8, 9 } }
Output : 1 4 7 8 9 2 5 6 3

Input : n = 3, m = 4
a[][] = { { 1, 2, 3 },
{ 4, 5, 6 },
{ 7, 8, 9 },
{ 10, 11, 12} }
Output : 1 4 7 10 11 12 2 5 8 9 3 6 ```

Observe there will be m (number of columns) number of L shapes that need to be traverse. So we will traverse each L shape in two parts, first vertical (top to down) and then horizontal (left to right).
To traverse in vertically, observe for each column j, 0 <= j <= m – 1, we need to traverse n – j elements vertically. So for each column j, traverse from a[j] to a[n-1-j][j].
Now, to traverse horizontally for each L shape, observe the corresponding row for each column j will be (n-1-j)th row and the first element will be (j+1)th element from the beginning of the row. So, for each L shape or for each column j, to traverse horizontally, traverse from a[n-1-j][j+1] to a[n-1-j][m-1].
Below is the implementation of this approach:

## C++

 `// C++ program to traverse a m x n matrix in L shape.``#include ``using` `namespace` `std;` `#define MAX 100` `// Printing matrix in L shape``void` `traverseLshape(``int` `a[][MAX], ``int` `n, ``int` `m)``{``    ``// for each column or each L shape``    ``for` `(``int` `j = 0; j < m; j++) {` `        ``// traversing vertically``        ``for` `(``int` `i = 0; i <= n - j - 1; i++)``            ``cout << a[i][j] << ``" "``;` `        ``// traverse horizontally``        ``for` `(``int` `k = j + 1; k < m; k++)``            ``cout << a[n - 1 - j][k] << ``" "``;``    ``}``}` `// Driven Program``int` `main()``{``    ``int` `n = 4;``    ``int` `m = 3;``    ``int` `a[][MAX] = { { 1, 2, 3 },``                     ``{ 4, 5, 6 },``                     ``{ 7, 8, 9 },``                     ``{ 10, 11, 12 } };``    ``traverseLshape(a, n, m);``    ``return` `0;``}`

## Java

 `// Java Program to traverse a m x n matrix in L shape.``public` `class` `GFG{` `    ``static` `void` `traverseLshape(``int` `a[][], ``int` `n, ``int` `m) {``        ``// for each column or each L shape``        ``for` `(``int` `j = ``0``; j < m; j++) {` `            ``// traversing vertically``            ``for` `(``int` `i = ``0``; i <= n - j - ``1``; i++)``                ``System.out.print(a[i][j] + ``" "``);` `            ``// traverse horizontally``            ``for` `(``int` `k = j + ``1``; k < m; k++)``                ``System.out.print(a[n - ``1` `- j][k] + ``" "``);``        ``}``    ``}` `    ``// Driver Code``    ``public` `static` `void` `main(String args[]) {``        ``int` `n = ``4``;``        ``int` `m = ``3``;``        ``int` `a[][] = { { ``1``, ``2``, ``3` `},``                        ``{ ``4``, ``5``, ``6` `},``                        ``{ ``7``, ``8``, ``9` `},``                        ``{ ``10``, ``11``, ``12` `} };``        ``traverseLshape(a, n, m);``    ``}``}`

## Python3

 `# Python3 program to traverse a``# m x n matrix in L shape.` `# Printing matrix in L shape``def` `traverseLshape(a, n, m):``    ` `    ``# for each column or each L shape``    ``for` `j ``in` `range``(``0``, m):` `        ``# traversing vertically``        ``for` `i ``in` `range``(``0``, n ``-` `j):``            ``print``(a[i][j], end ``=` `" "``);` `        ``# traverse horizontally``        ``for` `k ``in` `range``(j ``+` `1``, m):``            ``print``(a[n ``-` `1` `-` `j][k], end ``=` `" "``);` `# Driven Code``if` `__name__ ``=``=` `'__main__'``:``    ``n ``=` `4``;``    ``m ``=` `3``;``    ``a ``=` `[[``1``, ``2``, ``3``],``         ``[``4``, ``5``, ``6``],``         ``[``7``, ``8``, ``9``],``         ``[``10``, ``11``, ``12``]];``    ``traverseLshape(a, n, m);` `# This code is contributed by PrinciRaj1992`

## C#

 `// C# Program to traverse a m x n matrix in L shape.` `using` `System;` `public` `class` `GFG{``  ` `    ``static` `void` `traverseLshape(``int``[,] a, ``int` `n, ``int` `m) {``        ``// for each column or each L shape``        ``for` `(``int` `j = 0; j < m; j++) {``  ` `            ``// traversing vertically``            ``for` `(``int` `i = 0; i <= n - j - 1; i++)``                ``Console.Write(a[i,j] + ``" "``);``  ` `            ``// traverse horizontally``            ``for` `(``int` `k = j + 1; k < m; k++)``                ``Console.Write(a[n - 1 - j,k] + ``" "``);``        ``}``    ``}``  ` `    ``// Driver Code``    ``public` `static` `void` `Main() {``        ``int` `n = 4; ``        ``int` `m = 3; ``        ``int``[,] a = { { 1, 2, 3 }, ``                        ``{ 4, 5, 6 }, ``                        ``{ 7, 8, 9 }, ``                        ``{ 10, 11, 12 } }; ``        ``traverseLshape(a, n, m); ``    ``}``}`

## Javascript

 `   `
Output:
`1 4 7 10 11 12 2 5 8 9 3 6`

Time Complexity: O(n * m)

Auxiliary Space: O(1)

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