Given a square matrix of order n*n, we have to reverse the elements of both diagonals.
Examples:
Input : {1, 2, 3, 4, 5, 6, 7, 8, 9} Output :{9, 2, 7, 4, 5, 6, 3, 8, 1} Explanation: Major Diagonal Elements before: 1 5 9 After reverse: 9 5 1 Minor Diagonal Elements before: 3 5 7 After reverse: 7 5 3 Input :{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16} Output :{16, 2, 3, 13, 5, 11, 10, 8, 9, 7, 6, 12, 4, 14, 15, 1}
Implementation:
C++
#include <bits/stdc++.h> using namespace std;
#define N 4 // Function to swap diagonals elements void reverseDiagonal( int array[][N])
{ int i = 0, j = N;
while (i < j) {
// For reversing elements of major
// diagonal.
swap(array[i][i], array[j - 1][j - 1]);
// For reversing elements of minor
// diagonal.
swap(array[i][j - 1], array[j - 1][i]);
i++;
j--;
}
// Print matrix after reversals.
for ( int i = 0; i < N; ++i) {
for ( int j = 0; j < N; ++j)
printf ( "%d " , array[i][j]);
printf ( "\n" );
}
} // Driver function int main()
{ int matrix[N][N] = { 1, 2, 3, 4,
5, 6, 7, 8,
9, 10, 11, 12,
13, 14, 15, 16 };
reverseDiagonal(matrix);
return 0;
} |
Java
// Java Program to Reverse // Diagonal elements of matrix import java.io.*;
class GFG
{ static int N = 4 ;
// Function to swap // diagonals elements static void reverseDiagonal( int array[][])
{ int i = 0 , j = N;
int temp = 0 ;
while (i < j)
{
// For reversing elements
// of major diagonal.
temp = array[i][i];
array[i][i] = array[j - 1 ][j - 1 ];
array[j - 1 ][j - 1 ] = temp;
// For reversing elements
// of minor diagonal.
temp = array[i][j - 1 ];
array[i][j - 1 ] = array[j - 1 ][i];
array[j - 1 ][i] = temp;
i++;
j--;
}
// Print matrix after
// reversals.
for (i = 0 ; i < N; ++i)
{
for (j = 0 ; j < N; ++j)
System.out.print(array[i][j] + " " );
System.out.println();
}
} // Driver Code public static void main (String[] args)
{ int matrix[][] = {{ 1 , 2 , 3 , 4 },
{ 5 , 6 , 7 , 8 },
{ 9 , 10 , 11 , 12 },
{ 13 , 14 , 15 , 16 }};
reverseDiagonal(matrix);
} } // This code is contributed // by anuj_67. |
Python 3
# Python3 Program to Reverse # Diagonal elements of matrix N = 4
# Function to swap diagonals elements def reverseDiagonal(array):
i = 0
j = N
while (i < j) :
# For reversing elements of major
# diagonal.
array[i][i], array[j - 1 ][j - 1 ] = array[j - 1 ][j - 1 ], array[i][i]
# For reversing elements of minor
# diagonal.
array[i][j - 1 ], array[j - 1 ][i] = array[j - 1 ][i], array[i][j - 1 ]
i + = 1
j - = 1
# Print matrix after reversals.
for i in range (N):
for j in range ( N):
print ( array[i][j],end = " " )
print ()
# Driver function if __name__ = = "__main__" :
matrix = [[ 1 , 2 , 3 , 4 ],
[ 5 , 6 , 7 , 8 ],
[ 9 , 10 , 11 , 12 ],
[ 13 , 14 , 15 , 16 ]]
reverseDiagonal(matrix)
|
C#
// C# Program to Reverse // Diagonal elements of matrix using System;
class GFG
{ static int N = 4;
// Function to swap // diagonals elements static void reverseDiagonal( int [,]array)
{ int i = 0, j = N;
int temp = 0;
while (i < j)
{
// For reversing elements
// of major diagonal.
temp = array[i, i];
array[i, i] = array[j - 1, j - 1];
array[j - 1, j - 1] = temp;
// For reversing elements
// of minor diagonal.
temp = array[i, j - 1];
array[i, j - 1] = array[j - 1, i];
array[j - 1, i] = temp;
i++;
j--;
}
// Print matrix after
// reversals.
for (i = 0; i < N; ++i)
{
for (j = 0; j < N; ++j)
Console.Write(array[i, j] + " " );
Console.WriteLine();
}
} // Driver Code public static void Main ()
{ int [,]matrix = {{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 10, 11, 12},
{13, 14, 15, 16}};
reverseDiagonal(matrix);
} } // This code is contributed // by anuj_67. |
PHP
<?php // PHP Program to Reverse // Diagonal elements of matrix // Function to swap // diagonals elements function reverseDiagonal( $array )
{ $N = 4;
$i = 0; $j = $N ;
$temp = 0;
while ( $i < $j )
{
// For reversing elements
// of major diagonal.
$temp = $array [ $i ][ $i ];
$array [ $i ][ $i ] = $array [ $j - 1][ $j - 1];
$array [ $j - 1][ $j - 1] = $temp ;
// For reversing elements
// of minor diagonal.
$temp = $array [ $i ][ $j - 1];
$array [ $i ][ $j - 1] = $array [ $j - 1][ $i ];
$array [ $j - 1][ $i ] = $temp ;
$i ++;
$j --;
}
// Print matrix after
// reversals.
for ( $i = 0; $i < $N ; ++ $i )
{
for ( $j = 0; $j < $N ; ++ $j )
echo $array [ $i ][ $j ] . " " ;
echo "\n" ;
}
} // Driver Code $matrix = array ( array (1, 2, 3, 4),
array (5, 6, 7, 8),
array (9, 10, 11, 12),
array (13, 14, 15, 16));
reverseDiagonal( $matrix );
// This code is contributed // by Akanksha Rai |
Javascript
<script> // JavaScript Program to Reverse // Diagonal elements of matrix let N = 4; // Function to swap // diagonals elements function reverseDiagonal(array)
{ let i = 0, j = N;
let temp = 0;
while (i < j)
{
// For reversing elements
// of major diagonal.
temp = array[i][i];
array[i][i] = array[j - 1][j - 1];
array[j - 1][j - 1] = temp;
// For reversing elements
// of minor diagonal.
temp = array[i][j - 1];
array[i][j - 1] = array[j - 1][i];
array[j - 1][i] = temp;
i++;
j--;
}
// Print matrix after
// reversals.
for (i = 0; i < N; ++i)
{
for (j = 0; j < N; ++j)
document.write(array[i][j] + " " );
document.write( "<br>" );
}
} // Driver Code let matrix = [[1, 2, 3, 4],
[5, 6, 7, 8],
[9, 10, 11, 12],
[13, 14, 15, 16]];
reverseDiagonal(matrix);
// This code is contributed // by sravan kumar Gottumukkala </script> |
Output
16 2 3 13 5 11 10 8 9 7 6 12 4 14 15 1
Time Complexity: O(N2) for printing the matrix
Auxiliary Space: O(1)