Skip to content
Related Articles

Related Articles

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

View Discussion
Improve Article
Save Article
Like Article
  • Difficulty Level : Medium
  • Last Updated : 15 Jun, 2022

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

 

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.

C#




// C# implementation to sort the rows
// of matrix in ascending order followed by
// sorting the columns in descending order
using System;
 
public static class GFG {
     
    // function to sort each row of the matrix
    // according to the order specified by
    // ascending.
    static void sortByRow(int[, ] m)
    {
        // loop for rows of matrix
        for (int i = 0; i < m.GetLength(0); i++) {
 
            // loop for column of matrix
            for (int j = 0; j < m.GetLength(1); j++) {
 
                // loop for comparison and swapping
                for (int k = 0; k < m.GetLength(1) - j - 1;
                     k++) {
                    if (m[i, k] > m[i, k + 1]) {
 
                        // swapping of elements
                        int t = m[i, k];
                        m[i, k] = m[i, k + 1];
                        m[i, k + 1] = t;
                    }
                }
            }
        }
    }
 
    static void reverseArray(int[, ] arr)
    {
 
        // Traverse each row of [,]arr
        for (int i = 0; i < arr.GetLength(1); i++) {
 
            // Initialise start and end index
            int start = 0;
            int end = arr.GetLength(0) - 1;
 
            // Till start < end, swap the element
            // at start and end index
            while (start < end) {
 
                // Swap the element
                int temp = arr[i, start];
                arr[i, start] = arr[i, end];
                arr[i, end] = temp;
 
                // Increment start and decrement
                // end for next pair of swapping
                start++;
                end--;
            }
        }
    }
 
    // function to find transpose of the matrix
    public static void transpose(int[, ] 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
    public static void sortMatRowAndColWise(int[, ] mat,
                                            int n)
    {
        // sort rows of mat[][]
        sortByRow(mat);
 
        // get transpose of mat[][]
        transpose(mat, n);
 
        // again sort rows of mat[][] in descending
        // order.
        sortByRow(mat);
        reverseArray(mat);
 
        // again get transpose of mat[][]
        transpose(mat, n);
    }
 
    // function to print the matrix
    public static void printMat(int[, ] mat, int n)
    {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                Console.Write(mat[i, j]);
                Console.Write(" ");
            }
            Console.Write("\n");
        }
    }
 
    // Driver program to test above
    internal static void Main()
    {
        int n = 3;
 
        int[, ] mat
            = { { 3, 2, 1 }, { 9, 8, 7 }, { 6, 5, 4 } };
 
        Console.Write("Original Matrix:\n");
        printMat(mat, n);
 
        sortMatRowAndColWise(mat, n);
 
        Console.Write("\nMatrix After Sorting:\n");
        printMat(mat, n);
    }
}
 
// This code is contributed by Aarti_Rathi

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
?>

Javascript




<script>
// Javascript implementation to sort the rows
// of matrix in ascending order followed by
// sorting the columns in descending order
     
    let MAX_SIZE=10;
     
    // function to sort each row of the matrix
    // according to the order specified by
    // ascending.
    function sortByRow(mat,n,ascending)
    {
        for (let i = 0; i < n; i++)
        {
            if (ascending)
                mat[i].sort(function(a,b){return a-b;});
            else
                mat[i].sort(function(a,b){return b-a;});
        }    
    }
     
    // function to find transpose of the matrix
    function transpose(mat,n)
    {
        for (let i = 0; i < n; i++)
            for (let j = i + 1; j < n; j++)
            {
                // swapping element at index (i, j)
                // by element at index (j, i)
                let 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 (let i = 0; i < n; i++)
        {
            for (let j = 0; j < n; j++)
                document.write(mat[i][j] + " ");
            document.write("<br>");
        }
    }
     
    // Driver code
    let n = 3;
     
    let mat = [[3, 2, 1],
    [9, 8, 7],
    [6, 5, 4]];
     
    document.write("Original Matrix:<br>");
    printMat(mat, n);
      
    sortMatRowAndColWise(mat, n);
       
    document.write("\nMatrix After Sorting:<br>");
    printMat(mat, n);
     
     
    // This code is contributed by avanitrachhadiya2155
</script>

Output : 
 

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

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

Time Complexity: O(N2 log N)
Auxiliary Space: O(1)


My Personal Notes arrow_drop_up
Recommended Articles
Page :

Start Your Coding Journey Now!