# Diagonally Dominant Matrix

In mathematics, a square matrix is said to be diagonally dominant if for every row of the matrix, the magnitude of the diagonal entry in a row is larger than or equal to the sum of the magnitudes of all the other (non-diagonal) entries in that row. More precisely, the matrix A is diagonally dominant if

For example, The matrix

is diagonally dominant because
|a11| ≥ |a12| + |a13| since |+3| ≥ |-2| + |+1|
|a22| ≥ |a21| + |a23| since |-3| ≥ |+1| + |+2|
|a33| ≥ |a31| + |a32| since |+4| ≥ |-1| + |+2|

Given a matrix A of n rows and n columns. The task is tho check whether matrix A is diagonally dominant or not.

Examples :

```Input : A = { { 3, -2, 1 },
{ 1, -3, 2 },
{ -1, 2, 4 } };
Output : YES
Given matrix is diagonally dominant
because absolute value of every diagonal
element is more than sum of absolute values
of corresponding row.

Input : A = { { -2, 2, 1 },
{ 1, 3, 2 },
{ 1, -2, 0 } };
Output : NO
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

The idea is to run a loop from i = 0 to n-1 for the number of rows and for each row, run a loop j = 0 to n-1 find the sum of non-diagonal element i.e i != j. And check if diagonal element is greater than or equal to sum. If for any row, it is false, then return false or print “No”. Else print “YES”.

 `// CPP Program to check whether given matrix ` `// is Diagonally Dominant Matrix. ` `#include ` `#define N 3 ` `using` `namespace` `std; ` ` `  `// check the given given matrix is Diagonally ` `// Dominant Matrix or not. ` `bool` `isDDM(``int` `m[N][N], ``int` `n) ` `{ ` `    ``// for each row ` `    ``for` `(``int` `i = 0; i < n; i++) ` `   ``{         ` ` `  `        ``// for each column, finding sum of each row. ` `        ``int` `sum = 0; ` `        ``for` `(``int` `j = 0; j < n; j++)              ` `            ``sum += ``abs``(m[i][j]);         ` ` `  `        ``// removing the diagonal element. ` `        ``sum -= ``abs``(m[i][i]); ` ` `  `        ``// checking if diagonal element is less  ` `        ``// than sum of non-diagonal element. ` `        ``if` `(``abs``(m[i][i]) < sum)  ` `            ``return` `false``;  ` `        `  `    ``} ` ` `  `    ``return` `true``; ` `} ` ` `  `// Driven Program ` `int` `main() ` `{ ` `    ``int` `n = 3; ` `    ``int` `m[N][N] = { { 3, -2, 1 }, ` `                    ``{ 1, -3, 2 }, ` `                    ``{ -1, 2, 4 } }; ` ` `  `    ``(isDDM(m, n)) ? (cout << ``"YES"``) : (cout << ``"NO"``); ` ` `  `    ``return` `0; ` `} `

 `// JAVA Program to check whether given matrix ` `// is Diagonally Dominant Matrix. ` `import` `java.util.*; ` ` `  `class` `GFG { ` `     `  `    ``// check the given given matrix is Diagonally ` `    ``// Dominant Matrix or not. ` `    ``static` `boolean` `isDDM(``int` `m[][], ``int` `n) ` `    ``{ ` `        ``// for each row ` `        ``for` `(``int` `i = ``0``; i < n; i++) ` `        ``{         ` `      `  `            ``// for each column, finding  ` `            ``//sum of each row. ` `            ``int` `sum = ``0``; ` `            ``for` `(``int` `j = ``0``; j < n; j++)              ` `                ``sum += Math.abs(m[i][j]);         ` `      `  `            ``// removing the diagonal element. ` `            ``sum -= Math.abs(m[i][i]); ` `      `  `            ``// checking if diagonal element is less  ` `            ``// than sum of non-diagonal element. ` `            ``if` `(Math.abs(m[i][i]) < sum)  ` `                ``return` `false``;  ` `        `  `        ``} ` ` `  `        ``return` `true``; ` `    ``} ` ` `  `    ``/* Driver program to test above function */` `    ``public` `static` `void` `main(String[] args)  ` `    ``{ ` `        ``int` `n = ``3``; ` `        ``int` `m[][] = { { ``3``, -``2``, ``1` `}, ` `                      ``{ ``1``, -``3``, ``2` `}, ` `                      ``{ -``1``, ``2``, ``4` `} }; ` `      `  `        ``if` `(isDDM(m, n)) ` `             ``System.out.println(``"YES"``) ; ` `        ``else`   `            ``System.out.println(``"NO"``); ` `     `  `    ``} ` `} ` ` `  `// This code is contributed by  Arnav Kr. Mandal. `

 `# Python Program to check ` `# whether given matrix is  ` `# Diagonally Dominant Matrix. ` ` `  `# check the given given  ` `# matrix is Diagonally  ` `# Dominant Matrix or not. ` `def` `isDDM(m, n) : ` ` `  `    ``# for each row ` `    ``for` `i ``in` `range``(``0``, n) :          ` `     `  `        ``# for each column, finding ` `        ``# sum of each row. ` `        ``sum` `=` `0` `        ``for` `j ``in` `range``(``0``, n) : ` `            ``sum` `=` `sum` `+` `abs``(m[i][j])      ` ` `  `        ``# removing the  ` `        ``# diagonal element. ` `        ``sum` `=` `sum` `-` `abs``(m[i][i]) ` ` `  `        ``# checking if diagonal  ` `        ``# element is less than  ` `        ``# sum of non-diagonal ` `        ``# element. ` `        ``if` `(``abs``(m[i][i]) < ``sum``) : ` `            ``return` `False` ` `  `    ``return` `True` ` `  `# Driver Code ` `n ``=` `3` `m ``=` `[[ ``3``, ``-``2``, ``1` `], ` `    ``[ ``1``, ``-``3``, ``2` `], ` `    ``[ ``-``1``, ``2``, ``4` `]] ` ` `  `if``((isDDM(m, n))) : ` `    ``print` `(``"YES"``) ` `else` `: ` `    ``print` `(``"NO"``) ` ` `  `# This code is contributed by  ` `# Manish Shaw(manishshaw1) `

 `// C# Program to check whether given matrix ` `// is Diagonally Dominant Matrix. ` `using` `System; ` ` `  `class` `GFG { ` `     `  `    ``// check the given given matrix is Diagonally ` `    ``// Dominant Matrix or not. ` `    ``static` `bool` `isDDM(``int` `[,]m, ``int` `n) ` `    ``{ ` `        ``// for each row ` `        ``for` `(``int` `i = 0; i < n; i++) ` `        ``{  ` `     `  `            ``// for each column, finding  ` `            ``//sum of each row. ` `            ``int` `sum = 0; ` `            ``for` `(``int` `j = 0; j < n; j++)          ` `                ``sum += Math.Abs(m[i, j]);      ` `     `  `            ``// removing the diagonal element. ` `            ``sum -= Math.Abs(m[i, i]); ` `     `  `            ``// checking if diagonal element is less  ` `            ``// than sum of non-diagonal element. ` `            ``if` `(Math.Abs(m[i,i]) < sum)  ` `                ``return` `false``;  ` `         `  `        ``} ` ` `  `        ``return` `true``; ` `    ``} ` ` `  `    ``// Driver program  ` `    ``public` `static` `void` `Main()  ` `    ``{ ` `        ``int` `n = 3; ` `        ``int` `[,]m = { { 3, -2, 1 }, ` `                    ``{ 1, -3, 2 }, ` `                    ``{ -1, 2, 4 } }; ` `     `  `        ``if` `(isDDM(m, n)) ` `            ``Console.WriteLine(``"YES"``) ; ` `        ``else` `            ``Console.WriteLine(``"NO"``); ` `     `  `    ``} ` `} ` ` `  `// This code is contributed by Vt_m. `

 ` `

Output :
```YES
```

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Improved By : SanjuTomar, manishshaw1

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