Given a N*N matrix. The task is to convert the matrix to a diagonal matrix. That is to change the values of the non-diagonal elements of a matrix to 0.
Diagonal-Matrix: A matrix is called a Diagonal Matrix if all the non-diagonal elements of the matrix are zero.
Examples:
Input : mat[][] = {{ 2, 1, 7 },
{ 3, 7, 2 },
{ 5, 4, 9 }}
Output : {{2, 0, 7},
{0, 7, 0},
{5, 0, 9}}
Input : mat[][] = {{1, 3, 5, 6, 7},
{3, 5, 3, 2, 1},
{1, 2, 3, 4, 5},
{7, 9, 2, 1, 6},
{9, 1, 5, 3, 2}}
Output : {{1, 0, 0, 0, 7},
{0, 5, 0, 2, 0},
{0, 0, 3, 0, 0},
{0, 9, 0, 1, 0},
{9, 0, 0, 0, 2}}
Traverse all the non-diagonal elements of the matrix using two nested loops as shown in the below code and make them zero.
Below is the program to make all non-diagonal elements of a matrix zero:
C++
// C++ program to change the value of// non-diagonal elements of a matrix to 0#include <iostream>using namespace std;const int MAX = 100;// Function to print the resultant matrixvoid print(int mat[][MAX], int n, int m){ for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { cout << mat[i][j] << " "; } cout << endl; }}// Function to change the values of all// non-diagonal elements to 0void makenondiagonalzero(int mat[][MAX], int n, int m){ // Traverse all non-diagonal elements for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { if (i != j && i + j + 1 != n) // Change all non-diagonal // elements to zero mat[i][j] = 0; } } // print resultant matrix print(mat, n, m);}// Driver Codeint main(){ int mat[][MAX] = { { 2, 1, 7 }, { 3, 7, 2 }, { 5, 4, 9 } }; makenondiagonalzero(mat, 3, 3); return 0;} |
C
// C program to change the value of// non-diagonal elements of a matrix to 0#include <stdio.h>#define M 100#define N 100// Function to print the resultant matrixvoid print(int mat[M][N], int n, int m){ for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { printf("%d ",mat[i][j]); } printf("\n"); }}// Function to change the values of all// non-diagonal elements to 0void makenondiagonalzero(int mat[M][N], int n, int m){ // Traverse all non-diagonal elements for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { if (i != j && i + j + 1 != n) // Change all non-diagonal // elements to zero mat[i][j] = 0; } } // print resultant matrix print(mat, n, m);}// Driver Codeint main(){ int mat[][100] = { { 2, 1, 7 }, { 3, 7, 2 }, { 5, 4, 9 } }; makenondiagonalzero(mat, 3, 3); return 0;}// This code is contributed by kothvvsaakash. |
Java
// Java program to change the value of// non-diagonal elements of a matrix to 0import java.io.*;class GFG {static int MAX = 100;// Function to print the resultant matrixstatic void print(int mat[][], int n, int m){ for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { System.out.print( mat[i][j] + " "); } System.out.println(); }}// Function to change the values of all// non-diagonal elements to 0static void makenondiagonalzero(int mat[][], int n, int m){ // Traverse all non-diagonal elements for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { if (i != j && i + j + 1 != n) // Change all non-diagonal // elements to zero mat[i][j] = 0; } } // print resultant matrix print(mat, n, m);}// Driver Codepublic static void main (String[] args){ int mat[][] = { { 2, 1, 7 }, { 3, 7, 2 }, { 5, 4, 9 } }; makenondiagonalzero(mat, 3, 3);}}// This code is contributed by inder_verma |
Python3
# Python 3 program to change the value of # non-diagonal elements of a matrix to 0 # Function to print the resultant matrix def printmatrix(mat, n, m) : for i in range(n) : for j in range(m) : print(mat[i][j], end = " ") print()# Function to change the values # of all non-diagonal elements to 0 def makenondiagonalzero(mat, n, m) : # Traverse all non-diagonal elements for i in range(n) : for j in range(m) : if i != j and i + j + 1 != n : # Change all non-diagonal # elements to zero mat[i][j] = 0 # print resultant matrix printmatrix(mat, n, m) # Driver codeif __name__ == "__main__" : mat = [ [2, 1, 7], [3, 7, 2], [5, 4, 9] ] makenondiagonalzero(mat, 3, 3) # This code is contributed by Ryuga |
C#
// C# program to change the value // of non-diagonal elements of a // matrix to 0using System;class GFG { // static int MAX = 100;// Function to print the resultant// matrixstatic void print(int [,]mat, int n, int m){ for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { Console.Write(mat[i, j] + " "); } Console.WriteLine(); }}// Function to change the values of all// non-diagonal elements to 0static void makenondiagonalzero(int [,]mat, int n, int m){ // Traverse all non-diagonal elements for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { if (i != j && i + j + 1 != n) // Change all non-diagonal // elements to zero mat[i, j] = 0; } } // print resultant matrix print(mat, n, m);}// Driver Codepublic static void Main (){ int [,]mat = { { 2, 1, 7 }, { 3, 7, 2 }, { 5, 4, 9 } }; makenondiagonalzero(mat, 3, 3);}}// This code is contributed by anuj_67.. |
PHP
<?php// PHP program to change the value of // non-diagonal elements of a matrix to 0 // Function to print the resultant matrix function print1($mat, $n, $m) { for ($i = 0; $i < $n; $i++) { for ($j = 0; $j < $m; $j++) { echo $mat[$i][$j] . " "; } echo "\n"; } } // Function to change the values of// all non-diagonal elements to 0 function makenondiagonalzero($mat, $n, $m) { // Traverse all non-diagonal elements for ($i = 0; $i < $n; $i++) { for ($j = 0; $j < $m; $j++) { if ($i != $j && $i + $j + 1 != $n) // Change all non-diagonal // elements to zero $mat[$i][$j] = 0; } } // print resultant matrix print1($mat, $n, $m); } // Driver Code $mat = array( array( 2, 1, 7 ), array( 3, 7, 2 ), array( 5, 4, 9 ) ); makenondiagonalzero($mat, 3, 3); // This code is contributed// by Arnab Kundu?> |
Javascript
<script>// Java Script program to change the value of// non-diagonal elements of a matrix to 0let MAX = 100;// Function to print the resultant matrixfunction print(mat,n,m){ for (let i = 0; i < n; i++) { for (let j = 0; j < m; j++) { document.write( mat[i][j] + " "); } document.write("<br>"); }}// Function to change the values of all// non-diagonal elements to 0function makenondiagonalzero(mat,n,m){ // Traverse all non-diagonal elements for (let i = 0; i < n; i++) { for (let j = 0; j < m; j++) { if (i != j && i + j + 1 != n) // Change all non-diagonal // elements to zero mat[i][j] = 0; } } // print resultant matrix print(mat, n, m);}// Driver Code let mat = [[ 2, 1, 7 ], [ 3, 7, 2 ], [ 5, 4, 9 ]]; makenondiagonalzero(mat, 3, 3);// This code is contributed by sravan kumar G</script> |
Output:
2 0 7 0 7 0 5 0 9
Time complexity : O(n*m)
Auxiliary space: O(1) because it is using constant space, if space for input array is not considered
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