Print a matrix in Reverse Wave Form
Given a matrix, print it in Reverse Wave Form.
Examples :
Input : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Output : 4 8 12 16 15 11 7 3 2 6 10 14 13 9 5 1 Input : 1 9 4 10 3 6 90 11 2 30 85 72 6 31 99 15 Output : 10 11 72 15 99 85 90 4 9 6 30 31 6 2 3 1
Approach :To get the reverse wave form for a given matrix, we first print the elements of the last column of the matrix in downward direction then print the elements of the 2nd last column in the upward direction, then print the elements in third last column in downward direction and so on. For example 1, the flow goes like :
Below is the implementation to print reverse wave form of a matrix :
C++
// C++ implementation to print // reverse wave form of matrix #include<bits/stdc++.h> using namespace std; #define R 4 #define C 4 // function to print reverse wave // form for a given matrix void WavePrint( int m, int n, int arr[R][C]) { int i, j = n - 1, wave = 1; /* m - Ending row index n - Ending column index i, j - Iterator wave - for Direction wave = 1 - Wave direction down wave = 0 - Wave direction up */ while (j >= 0) { // Check whether to go in // upward or downward if (wave == 1) { // Print the element of the matrix // downward since the value of wave = 1 for (i = 0; i < m; i++) cout << arr[i][j] << " " ; wave = 0; j--; } else { // Print the elements of the // matrix upward since the value // of wave = 0 for (i = m - 1; i >= 0; i--) cout << arr[i][j] << " " ; wave = 1; j--; } } } // driver function int main() { int arr[R][C] = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 }, { 13, 14, 15, 16 } }; WavePrint(R, C, arr); return 0; } |
Java
// Java implementation to print // reverse wave form of matrix import java.io.*; class GFG { static int R = 4 ; static int C = 4 ; // function to print reverse wave // form for a given matrix static void WavePrint( int m, int n, int arr[][]) { int i, j = n - 1 , wave = 1 ; // m- Ending row index //n - Ending column index //i, j - Iterator //wave - for Direction //wave = 1 - Wave direction down //wave = 0 - Wave direction up */ while (j >= 0 ) { // Check whether to go in // upward or downward if (wave == 1 ) { // Print the element of the matrix // downward since the value of wave = 1 for (i = 0 ; i < m; i++) System.out.print(arr[i][j] + " " ); wave = 0 ; j--; } else { // Print the elements of the // matrix upward since the value // of wave = 0 for (i = m - 1 ; i >= 0 ; i--) System.out.print( arr[i][j] + " " ); wave = 1 ; j--; } } } // Driver function public static void main (String[] args) { int arr[][] = { { 1 , 2 , 3 , 4 }, { 5 , 6 , 7 , 8 }, { 9 , 10 , 11 , 12 }, { 13 , 14 , 15 , 16 } }; WavePrint(R, C, arr); } } // This code is contributed by vt_m |
Python3
# Python3 implementation to print # reverse wave form of matrix R = 4 C = 4 # function to print reverse wave # form for a given matrix def wavePrint(m, n, arr): j = n - 1 wave = 1 # m - Ending row index # n - Ending column index # i, j - Iterator # wave - for Direction # wave = 1 - Wave direction down # wave = 0 - Wave direction up while j > = 0 : # Check whether to go in # upward or downward if wave = = 1 : # Print the element of the # matrix downward since the # value of wave = 1 for i in range (m): print (arr[i][j], end = " " ), wave = 0 j - = 1 else : # Print the elements of the # matrix upward since the # value of wave = 0 for i in range (m - 1 , - 1 , - 1 ): print (arr[i][j], end = " " ), wave = 1 j - = 1 # Driver code arr = [ [ 1 , 2 , 3 , 4 ], [ 5 , 6 , 7 , 8 ], [ 9 , 10 , 11 , 12 ], [ 13 , 14 , 15 , 16 ] ] wavePrint(R, C, arr) # This code is contributed by # Upendra Singh Bartwal |
C#
// C# implementation to print // reverse wave form of matrix using System; class GFG { static int R = 4; static int C = 4; // function to print reverse wave // form for a given matrix static void WavePrint( int m, int n, int [,]arr) { int i, j = n - 1, wave = 1; // m- Ending row index // n - Ending column index // i, j - Iterator // wave - for Direction // wave = 1 - Wave direction down // wave = 0 - Wave direction up */ while (j >= 0) { // Check whether to go in // upward or downward if (wave == 1) { // Print the element of the // matrix downward since the // value of wave = 1 for (i = 0; i < m; i++) Console.Write(arr[i,j] + " " ); wave = 0; j--; } else { // Print the elements of the // matrix upward since the value // of wave = 0 for (i = m - 1; i >= 0; i--) Console.Write( arr[i,j] + " " ); wave = 1; j--; } } } // Driver function public static void Main () { int [,]arr = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 }, { 13, 14, 15, 16 } }; WavePrint(R, C, arr); } } // This code is contributed by vt_m. |
PHP
<?php // PHP implementation to print // reverse wave form of matrix $R = 4; $C = 4; // function to print reverse // wave form for a given matrix function WavePrint( $m , $n , $arr ) { global $R ; global $C ; $i ; $j = $n - 1; $wave = 1; /* m - Ending row index n - Ending column index i, j - Iterator wave - for Direction wave = 1 - Wave direction down wave = 0 - Wave direction up */ while ( $j >= 0) { // Check whether to go in // upward or downward if ( $wave == 1) { // Print the element of the // matrix downward since the // value of wave = 1 for ( $i = 0; $i < $m ; $i ++) echo $arr [ $i ][ $j ] , " " ; $wave = 0; $j --; } else { // Print the elements of // the matrix upward since // the value of wave = 0 for ( $i = $m - 1; $i >= 0; $i --) echo $arr [ $i ][ $j ] , " " ; $wave = 1; $j --; } } } // Driver Code $arr = array ( array (1, 2, 3, 4), array (5, 6, 7, 8), array (9, 10, 11, 12), array (13, 14, 15, 16)); WavePrint( $R , $C , $arr ); // This code is contributed by ajit ?> |
Javascript
<script> // Javascript implementation to print // reverse wave form of matrix R = 4 C = 4 // Function to print reverse wave // form for a given matrix function WavePrint(m, n, arr) { var i, j = n - 1, wave = 1; /* m - Ending row index n - Ending column index i, j - Iterator wave - for Direction wave = 1 - Wave direction down wave = 0 - Wave direction up */ while (j >= 0) { // Check whether to go in // upward or downward if (wave == 1) { // Print the element of the matrix // downward since the value of wave = 1 for (i = 0; i < m; i++) document.write( arr[i][j] + " " ); wave = 0; j--; } else { // Print the elements of the // matrix upward since the value // of wave = 0 for (i = m - 1; i >= 0; i--) document.write( arr[i][j] + " " ); wave = 1; j--; } } } // Driver code var arr = [ [ 1, 2, 3, 4 ], [ 5, 6, 7, 8 ], [ 9, 10, 11, 12 ], [ 13, 14, 15, 16 ] ]; WavePrint(R, C, arr); // This code is contributed by itsok </script> |
Output
4 8 12 16 15 11 7 3 2 6 10 14 13 9 5 1
Complexity Analysis
- Time Complexity: O(N2)
- Auxiliary Space: O(1)
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