# C++ Program to Sort the matrix row-wise and column-wise

• Difficulty Level : Medium
• Last Updated : 18 Jan, 2022

Given a n x n matrix. The problem is to sort the matrix row-wise and column wise.
Examples:

```Input : mat[][] = { {4, 1, 3},
{9, 6, 8},
{5, 2, 7} }
Output : 1 3 4
2 5 7
6 8 9

Input : mat[][] = { {12, 7, 1, 8},
{20, 9, 11, 2},
{15, 4, 5, 13},
{3, 18, 10, 6} }
Output : 1 5 8 12
2 6 10 15
3 7 11 18
4 9 13 20```

Approach: Following are the steps:

1. Sort each row of the matrix.
2. Get transpose of the matrix.
3. Again sort each row of the matrix.
4. Again get transpose of the matrix.

Algorithm for sorting each row of matrix using C++ STL sort():

```for (int i = 0 ; i < n; i++)
sort(mat[i], mat[i] + n);```

Algorithm for getting transpose of the matrix:

```for (int i = 0; i < n; i++) {
for (int j = i + 1; i < n; i++) {
int temp = mat[i][j];
mat[i][j] = mat[j][i];
mat[j][i] = temp;
}
}```

## C++

 `// C++ implementation to sort the matrix row-wise ` `// and column-wise ` `#include ` ` `  `using` `namespace` `std; ` ` `  `#define MAX_SIZE 10 ` ` `  `// function to sort each row of the matrix ` `void` `sortByRow(``int` `mat[MAX_SIZE][MAX_SIZE], ``int` `n) ` `{ ` `    ``for` `(``int` `i = 0; i < n; i++) ` ` `  `        ``// sorting row number 'i' ` `        ``sort(mat[i], mat[i] + n); ` `} ` ` `  `// function to find transpose of the matrix ` `void` `transpose(``int` `mat[MAX_SIZE][MAX_SIZE], ``int` `n) ` `{ ` `    ``for` `(``int` `i = 0; i < n; i++) ` `        ``for` `(``int` `j = i + 1; j < n; j++)  ` ` `  `            ``// swapping element at index (i, j)  ` `            ``// by element at index (j, i) ` `            ``swap(mat[i][j], mat[j][i]); ` `} ` ` `  `// function to sort the matrix row-wise ` `// and column-wise ` `void` `sortMatRowAndColWise(``int` `mat[MAX_SIZE][MAX_SIZE], ` `                                               ``int` `n) ` `{ ` `    ``// sort rows of mat[][] ` `    ``sortByRow(mat, n); ` ` `  `    ``// get transpose of mat[][] ` `    ``transpose(mat, n); ` ` `  `    ``// again sort rows of mat[][] ` `    ``sortByRow(mat, n); ` ` `  `    ``// again get transpose of mat[][] ` `    ``transpose(mat, n); ` `} ` ` `  `// function to print the matrix ` `void` `printMat(``int` `mat[MAX_SIZE][MAX_SIZE], ``int` `n) ` `{ ` `    ``for` `(``int` `i = 0; i < n; i++) { ` `        ``for` `(``int` `j = 0; j < n; j++) ` `            ``cout << mat[i][j] << ``" "``; ` `        ``cout << endl; ` `    ``} ` `} ` ` `  `// Driver program to test above ` `int` `main() ` `{ ` `    ``int` `mat[MAX_SIZE][MAX_SIZE] = { { 4, 1, 3 }, ` `                            ``{ 9, 6, 8 }, ` `                            ``{ 5, 2, 7 } }; ` `    ``int` `n = 3; ` ` `  `    ``cout << "Original Matrix: ` `"; ` `    ``printMat(mat, n); ` ` `  `    ``sortMatRowAndColWise(mat, n); ` ` `  `    ``cout << " ` `Matrix After Sorting: ` `"; ` `    ``printMat(mat, n); ` ` `  `    ``return` `0; ` `} `

Output:

```Original Matrix:
4 1 3
9 6 8
5 2 7

Matrix After Sorting:
1 3 4
2 5 7
6 8 9```

Time Complexity: O(n2log2n).
Auxiliary Space: O(1).
Please refer complete article on Sort the matrix row-wise and column-wise for more details!

My Personal Notes arrow_drop_up
Related Articles