Sort given Array which is already Sorted based on absolute values of elements
Given an array arr[] of size N, sorted based on the absolute value of its elements. The task is to sort this array based on the actual values of the elements.
Examples:
Input: arr[] = {5, -7, 10, -11, 18}
Output: -11, -7, 5, 10, 18
Explanation: When the array is sorted the negative values will come at the beginning of the array.Input: arr[] = {1, -2, -3, 4, -5}
Output: -5, -3, -2, 1, 4
Naive Approach:
The naive approach to solve the problem is to use inbuilt sort function to sort the array.
Algorithm:
- Take the input array arr[] of size N as input.
- Use the inbuilt sort function to sort the array in ascending order based on the absolute values of the elements.
- Print the sorted array.
Below is the implementation of the approach:
C++
#include<bits/stdc++.h> using namespace std; // Driver code int main() { // Input array int arr[] = { 1, -2, 3, -4, -5, 6 }; int n = sizeof (arr) / sizeof (arr[0]); // sort array in ascending order sort(arr, arr + n); // print the final array elements for ( int i=0; i<n; i++) { cout<<arr[i]<< " " ; } return 0; } |
-5 -4 -2 1 3 6
Time Complexity: O(N*logN) as sort function has been called. Here, N is size of input array.
Space Complexity: O(1) as no extra space has been used.
Approach: This problem can be solved using double ended queue. The idea is to traverse the array from left to right and insert the negative elements in the front and the positive elements in the back of the deque. Now pop the elements from the front of the deque to fill the array and get the answer.
Below is the implementation of the above approach:
C++
// C++ program for the above approach #include <deque> #include <iostream> using namespace std; // Function to sort void SortWithoutSorting( int arr[], int N) { deque< int > dq; for ( int i = 0; i < N; i++) { // Pushing negative elements in // the front of the deque if (arr[i] < 0) { dq.push_front(arr[i]); } // Pushing positive elements in // the back of the deque else { dq.push_back(arr[i]); } } // Preparing the output array int i = 0; for ( auto it = dq.begin(); it != dq.end(); it++) arr[i++] = *it; } // Function to print the array. void showArray( int arr[], int N) { for ( int i = 0; i < N; i++) { cout << arr[i] << " " ; } } // Driver Code int main() { int arr[] = { 1, -2, 3, -4, -5, 6 }; int N = sizeof (arr) / sizeof ( int ); SortWithoutSorting(arr, N); showArray(arr, N); return 0; } |
Java
// Java Program for the above approach import java.util.*; class GFG { // Function to sort public static void SortWithoutSorting( int arr[], int N) { Deque<Integer> dq = new ArrayDeque<Integer>(); for ( int i = 0 ; i < N; i++) { // Pushing negative elements in // the front of the deque if (arr[i] < 0 ) { dq.addFirst(arr[i]); } // Pushing positive elements in // the back of the deque else { dq.addLast(arr[i]); } } // Preparing the output array int i = 0 ; for (Iterator it = dq.iterator(); it.hasNext();) { arr[i++] = ( int )it.next(); } } // Function to print the array. public static void showArray( int arr[], int N) { for ( int i = 0 ; i < N; i++) { System.out.print(arr[i] + " " ); } } // Driver Code public static void main (String[] args) { int arr[] = { 1 , - 2 , 3 , - 4 , - 5 , 6 }; int N = arr.length; SortWithoutSorting(arr, N); showArray(arr, N); } } // This code is contributed by Shubham Singh |
Python3
# Python code for the above approach # Function to sort def SortWithoutSorting(arr, N): dq = [] for i in range (N): # Pushing negative elements in # the front of the deque if (arr[i] < 0 ): dq.insert( 0 ,arr[i]) # Pushing positive elements in # the back of the deque else : dq.append(arr[i]) # Preparing the output array i = 0 for it in dq: arr[i] = it i + = 1 return arr # Function to print the array. def showArray(arr, N): for i in range (N): print (arr[i], end = " " ) # Driver Code arr = [ 1 , - 2 , 3 , - 4 , - 5 , 6 ] N = len (arr) arr = SortWithoutSorting(arr, N) showArray(arr, N) # This code is contributed by Shubham Singh |
C#
// C# Program for the above approach using System; using System.Collections.Generic; public class GFG{ // Function to sort public static void SortWithoutSorting( int [] arr, int N) { List< int > dq = new List< int >(); int i; for (i = 0; i < N; i++) { // Pushing negative elements in // the front of the deque if (arr[i] < 0) { dq.Insert(0,arr[i]); } // Pushing positive elements in // the back of the deque else { dq.Add(arr[i]); } } // Preparing the output array i = 0; foreach ( int it in dq) { arr[i++] = it; } } // Function to print the array. public static void showArray( int [] arr, int N) { for ( int i = 0; i < N; i++) { Console.Write(arr[i] + " " ); } } // Driver Code public static void Main () { int [] arr = { 1, -2, 3, -4, -5, 6 }; int N = arr.Length; SortWithoutSorting(arr, N); showArray(arr, N); } } // This code is contributed by Shubham Singh |
Javascript
<script> // JavaScript code for the above approach // Function to sort function SortWithoutSorting(arr, N) { let dq = []; for (let i = 0; i < N; i++) { // Pushing negative elements in // the front of the deque if (arr[i] < 0) { dq.unshift(arr[i]); } // Pushing positive elements in // the back of the deque else { dq.push(arr[i]); } } // Preparing the output array let i = 0; for (let it of dq) arr[i++] = it; } // Function to print the array. function showArray(arr, N) { for (let i = 0; i < N; i++) { document.write(arr[i] + " " ) } } // Driver Code let arr = [1, -2, 3, -4, -5, 6]; let N = arr.length; SortWithoutSorting(arr, N); showArray(arr, N); // This code is contributed by Potta Lokesh </script> |
-5 -4 -2 1 3 6
Time complexity: O(N)
Auxiliary Space: O(N)
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