Sorting rows of matrix in ascending order followed by columns in descending order

Last Updated: 26-12-2018

Given a matrix, sort the rows of matrix in ascending order followed by sorting the columns in descending order.
Examples :

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

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

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

1) Traverse all rows one by one and sort rows in ascending order using simple array sort.
2) Convert matrix to its transpose
3) Again sort all rows, but this time in ascending order.
4) Again convert matrix to its transpose

C++

// C++ implementation to sort the rows 
// of matrix in ascending order followed by 
// sorting the columns in descending order 
#include <bits/stdc++.h> 
using namespace std; 
  
#define MAX_SIZE 10 
  
// function to sort each row of the matrix 
// according to the order specified by  
// ascending. 
void sortByRow(int mat[][MAX_SIZE], int n,  
                           bool ascending) 
{ 
    for (int i = 0; i < n; i++) 
    { 
      if (ascending)     
        sort(mat[i], mat[i] + n); 
      else
          sort(mat[i], mat[i] + n, greater<int>()); 
    }       
} 
  
// function to find transpose of the matrix 
void transpose(int mat[][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], 
                                       int n) 
{ 
    // sort rows of mat[][] 
    sortByRow(mat, n, true); 
  
    // get transpose of mat[][] 
    transpose(mat, n); 
  
    // again sort rows of mat[][] in descending 
    // order. 
    sortByRow(mat, n, false); 
  
    // again get transpose of mat[][] 
    transpose(mat, n); 
} 
  
// function to print the matrix 
void printMat(int mat[][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 n = 3; 
      
    int mat[n][MAX_SIZE]  = {{3, 2, 1}, 
                            {9, 8, 7},  
                            {6, 5, 4}}; 
  
    cout << "Original Matrix:\n"; 
    printMat(mat, n); 
  
    sortMatRowAndColWise(mat, n); 
  
    cout << "\nMatrix After Sorting:\n"; 
    printMat(mat, n); 
  
    return 0; 
} 

Java

// Java implementation to sort the rows 
// of matrix in ascending order followed by 
// sorting the columns in descending order 
import java.util.Arrays; 
import java.util.Collections; 
  
class GFG 
{ 
    static int MAX_SIZE=10; 
      
    // function to sort each row of the matrix 
    // according to the order specified by  
    // ascending. 
    static void sortByRow(Integer mat[][], int n,  
                                 boolean ascending) 
    { 
        for (int i = 0; i < n; i++) 
        { 
            if (ascending)  
                Arrays.sort(mat[i]); 
            else
                Arrays.sort(mat[i],Collections.reverseOrder()); 
        }      
    } 
      
    // function to find transpose of the matrix 
    static void transpose(Integer mat[][], 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) 
                int temp = mat[i][j]; 
                mat[i][j] = mat[j][i]; 
                mat[j][i] = temp; 
            } 
    } 
      
    // function to sort the matrix row-wise 
    // and column-wise 
    static void sortMatRowAndColWise(Integer mat[][], 
                                              int n) 
    { 
        // sort rows of mat[][] 
        sortByRow(mat, n, true); 
      
        // get transpose of mat[][] 
        transpose(mat, n); 
      
        // again sort rows of mat[][] in descending 
        // order. 
        sortByRow(mat, n, false); 
      
        // again get transpose of mat[][] 
        transpose(mat, n); 
    } 
      
    // function to print the matrix 
    static void printMat(Integer mat[][], int n) 
    { 
        for (int i = 0; i < n; i++)  
        { 
            for (int j = 0; j < n; j++) 
                System.out.print(mat[i][j] + " "); 
            System.out.println(); 
        } 
    } 
      
    // Driver code 
    public static void main (String[] args)  
    { 
        int n = 3; 
          
        Integer mat[][] = {{3, 2, 1}, 
                           {9, 8, 7},  
                           {6, 5, 4}}; 
      
        System.out.print("Original Matrix:\n"); 
        printMat(mat, n); 
      
        sortMatRowAndColWise(mat, n); 
      
        System.out.print("\nMatrix After Sorting:\n"); 
        printMat(mat, n); 
    } 
} 
  
// This code is contributed by Anant Agarwal. 

Python3

# Python implementation to sort the rows 
# of matrix in ascending order followed by 
# sorting the columns in descending order 
  
MAX_SIZE=10
   
# function to sort each row of the matrix 
# according to the order specified by  
# ascending. 
def sortByRow(mat, n, ascending): 
  
    for i in range(n): 
        if (ascending):     
            mat[i].sort() 
        else: 
            mat[i].sort(reverse=True) 
   
# function to find  
# transpose of the matrix 
def transpose(mat, n): 
  
    for i in range(n): 
        for j in range(i + 1, n):  
          
            # swapping element at index (i, j)  
            # by element at index (j, i) 
            temp = mat[i][j] 
            mat[i][j] = mat[j][i] 
            mat[j][i] = temp 
  
# function to sort  
# the matrix row-wise 
# and column-wise 
def sortMatRowAndColWise(mat, n): 
  
    # sort rows of mat[][] 
    sortByRow(mat, n, True) 
   
    # get transpose of mat[][] 
    transpose(mat, n) 
   
    # again sort rows of  
    # mat[][] in descending 
    # order. 
    sortByRow(mat, n, False) 
   
    # again get transpose of mat[][] 
    transpose(mat, n) 
   
# function to print the matrix 
def printMat(mat, n): 
  
    for i in range(n): 
        for j in range(n): 
            print(mat[i][j] , " ", end="") 
        print() 
  
#Driver code 
n = 3
       
mat = [[3, 2, 1], 
    [9, 8, 7],  
    [6, 5, 4]] 
   
print("Original Matrix:") 
printMat(mat, n) 
   
sortMatRowAndColWise(mat, n) 
   
print("Matrix After Sorting:") 
printMat(mat, n) 
  
# This code is contributed 
# by Anant Agarwal. 

PHP

<?php  
// PHP implementation to sort the rows 
// of matrix in ascending order followed by 
// sorting the columns in descending order 
$MAX_SIZE = 10; 
  
// function to sort each row of the matrix 
// according to the order specified by  
// ascending. 
function sortByRow(&$mat, $n, $ascending) 
{ 
    for ($i = 0; $i < $n; $i++) 
    { 
        if ($ascending)  
            sort($mat[$i]); 
        else
            rsort($mat[$i]); 
    }      
} 
  
// function to find transpose 
// of the matrix 
function transpose(&$mat, $n) 
{ 
    for ($i = 0; $i < $n; $i++) 
    { 
        for ($j = $i + 1; $j < $n; $j++)  
        { 
            // swapping element at index (i, j)  
            // by element at index (j, i) 
            $temp = $mat[$i][$j]; 
            $mat[$i][$j] = $mat[$j][$i]; 
            $mat[$j][$i] = $temp; 
        } 
    } 
} 
  
// function to sort the matrix row-wise 
// and column-wise 
function sortMatRowAndColWise(&$mat, $n) 
{ 
    // sort rows of mat[][] 
    sortByRow($mat, $n, true); 
  
    // get transpose of mat[][] 
    transpose($mat, $n); 
  
    // again sort rows of mat[][] in  
    // descending order. 
    sortByRow($mat, $n, false); 
  
    // again get transpose of mat[][] 
    transpose($mat, $n); 
} 
  
// function to print the matrix 
function printMat(&$mat, $n) 
{ 
    for ($i = 0; $i < $n; $i++)  
    { 
        for ($j = 0; $j < $n; $j++) 
            echo $mat[$i][$j] . " "; 
        echo "\n" ; 
    } 
} 
  
// Driver Code 
$n = 3; 
  
$mat = array(array(3, 2, 1), 
             array(9, 8, 7),  
             array(6, 5, 4)); 
  
echo "Original Matrix:\n"; 
printMat($mat, $n); 
  
sortMatRowAndColWise($mat, $n); 
  
echo "\nMatrix After Sorting:\n"; 
printMat($mat, $n); 
  
// This code is contributed by Ita_c 
?> 

Output :

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

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

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