Given a square matrix of order n*n, you have to interchange the elements of both diagonals.
Examples :
Input : matrix[][] = {1, 2, 3,
4, 5, 6,
7, 8, 9}
Output : matrix[][] = {3, 2, 1,
4, 5, 6,
9, 8, 7}
Input : matrix[][] = {4, 2, 3, 1,
5, 7, 6, 8,
9, 11, 10, 12,
16, 14, 15, 13}
Output : matrix[][] = {1, 2, 3, 4,
5, 6, 7, 8,
9, 10, 11, 12,
11, 14, 15, 16}
Explanation : Idea behind interchanging diagonals of a square matrix is simple. Iterate from 0 to n-1 and for each iteration you have to swap a[i][i] and a[i][n-i-1].
Java
// Java program to interchange// the diagonals of matriximport java.io.*;class GFG{ public static int N = 3; // Function to interchange diagonals static void interchangeDiagonals(int array[][]) { // swap elements of diagonal for (int i = 0; i < N; ++i) if (i != N / 2) { int temp = array[i][i]; array[i][i] = array[i][N - i - 1]; array[i][N - i - 1] = temp; } for (int i = 0; i < N; ++i) { for (int j = 0; j < N; ++j) System.out.print(array[i][j]+" "); System.out.println(); } } // Driver Code public static void main (String[] args) { int array[][] = { {4, 5, 6}, {1, 2, 3}, {7, 8, 9} }; interchangeDiagonals(array); }}// This code is contributed by Pramod Kumar |
Output:
6 5 4 1 2 3 9 8 7
Time Complexity: O(N) where N is no of rows or columns; as we are using a single loop for interchanging diagonals of a given matrix.
Auxiliary Space: O(1), as we are not using any extra space.
Please refer complete article on Program to Interchange Diagonals of Matrix for more details!
