Given a N * M matrix. The task is to traverse the given matrix in L shape as shown in below image.
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[0][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 <iostream> 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] << " " ; } } // Driver 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
<script> // Javascript program to traverse a m x n matrix in L shape. var MAX = 100; // Printing matrix in L shape function traverseLshape(a, n, m) { // for each column or each L shape for ( var j = 0; j < m; j++) { // traversing vertically for ( var i = 0; i <= n - j - 1; i++) document.write( a[i][j] + " " ); // traverse horizontally for ( var k = j + 1; k < m; k++) document.write( a[n - 1 - j][k] + " " ); } } // Driver Program var n = 4; var m = 3; var a = [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ], [ 10, 11, 12 ] ]; traverseLshape(a, n, m); </script> |
1 4 7 10 11 12 2 5 8 9 3 6
Complexity Analysis:
- Time Complexity: O(n * m)
- Auxiliary Space: O(1)
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