# Sort the array using slow sort

• Last Updated : 22 Jun, 2021

Given an array arr[] consisting of N integers, the task is to sort the given array in ascending order using the slow sort.

Examples:

Input: arr[] = {6, 8, 9, 4, 12, 1}
Output: 1 4 6 8 9 12

Input: arr[] = {5, 4, 3, 2, 1}
Output: 1 2 3 4 5

Approach: Like Merge Sort, Slow Sort is a Divide and Conquer algorithm. It divides the input array into two halves, calls itself the two halves, and then compares the maximum element of the two halves. It stores the maximum element of a sub-array at the top position of the sub-array, then, it recursively calls the sub-array without the maximum element. Follow the steps below to solve the problem:

SlowSort(arr[], l, r):

• If r >= l, perform the following steps:
• Find the middle value of the array as m = (l + r) / 2.
• Recursively call function SlowSort to find the maximum of first half elements: SlowSort(arr, l, m)
• Recursively call function SlowSort to find the maximum of second-half elements: SlowSort(arr, m + 1, r)
• Store the largest of two maxima returned from the above function calls at the end as arr[r] = max(arr[m], arr[r])
• Recursively call function SlowSort without the maximum obtained in the above step: SlowSort(arr, l, r-1)

The following figure shows the complete Slow Sort process. For example, array {9, 6, 8, 4, 1, 3, 7, 2}. From the figure, it can be observed that the array is recursively divided into two halves till the size becomes 1. Once the size becomes 1, the comparison process begins.

Slow Sort

Below is the implementation for the above approach:

## C++

 // C++ program for the above approach #include  using namespace std;   // Function to swap two elements void swap(int* xp, int* yp) {     int temp = *xp;     *xp = *yp;     *yp = temp; }   // Function to sort the array using // the Slow sort void slow_sort(int A[], int i, int j) {     // Recursion break condition     if (i >= j)         return;       // Store the middle value     int m = (i + j) / 2;       // Recursively call with the     // left half     slow_sort(A, i, m);       // Recursively call with the     // right half     slow_sort(A, m + 1, j);       // Swap if the first element is     // lower than second     if (A[j] < A[m]) {         swap(&A[j], &A[m]);     }       // Recursively call with the     // array excluding the maximum     // element     slow_sort(A, i, j - 1); }   // Function to print the array void printArray(int arr[], int size) {     int i;     for (i = 0; i < size; i++)         cout << arr[i] << " ";     cout << endl; }   // Driver Code int main() {     // Given Input     int arr[] = { 6, 8, 9, 4, 12, 1 };     int n = sizeof(arr) / sizeof(arr[0]);       // Function Call     slow_sort(arr, 0, n - 1);       // Print the sorted array     printArray(arr, n);       return 0; }

## Java

 // Java program for the above approach class GFG{   // Function to sort the array using // the Slow sort static void slow_sort(int A[], int i, int j) {           // Recursion break condition     if (i >= j)         return;       // Store the middle value     int m = (i + j) / 2;       // Recursively call with the     // left half     slow_sort(A, i, m);       // Recursively call with the     // right half     slow_sort(A, m + 1, j);       // Swap if the first element is     // lower than second     if (A[j] < A[m])      {         int temp = A[j];         A[j] = A[m];         A[m] = temp;     }       // Recursively call with the     // array excluding the maximum     // element     slow_sort(A, i, j - 1); }   // Function to print the array static void printArray(int arr[], int size) {     int i;     for(i = 0; i < size; i++)         System.out.print(arr[i] + " ");               System.out.println(); }   // Driver code public static void main(String[] args) {     int arr[] = { 6, 8, 9, 4, 12, 1 };     int n = arr.length;       // Function Call     slow_sort(arr, 0, n - 1);       // Print the sorted array     printArray(arr, n); } }   // This code is contributed by abhinavjain194

## Python3

 # Python3 program for the above approach   # Function to sort the array using # the Slow sort def slow_sort(A, i, j):           # Recursion break condition     if (i >= j):         return               # Store the middle value     m = (i + j) // 2           # Recursively call with the     # left half     slow_sort(A, i, m)       # Recursively call with the     # right half     slow_sort(A, m + 1, j)       # Swap if the first element is     # lower than second     if (A[j] < A[m]):         temp = A[m]         A[m] = A[j]         A[j] = temp       # Recursively call with the     # array excluding the maximum     # element     slow_sort(A, i, j - 1)   # Function to print the array def printArray(arr, size):           for i in range(size):         print(arr[i], end = " ")   # Driver Code if __name__ == '__main__':           arr = [ 6, 8, 9, 4, 12, 1 ]     n = len(arr)           # Function Call     slow_sort(arr, 0, n - 1)           # Print the sorted array     printArray(arr, n)   # This code is contributed by SoumikMondal

## C#

 // C# implementation of the approach  using System;   class GFG  {     // Function to sort the array using // the Slow sort static void slow_sort(int[] A, int i, int j) {           // Recursion break condition     if (i >= j)         return;       // Store the middle value     int m = (i + j) / 2;       // Recursively call with the     // left half     slow_sort(A, i, m);       // Recursively call with the     // right half     slow_sort(A, m + 1, j);       // Swap if the first element is     // lower than second     if (A[j] < A[m])      {         int temp = A[j];         A[j] = A[m];         A[m] = temp;     }       // Recursively call with the     // array excluding the maximum     // element     slow_sort(A, i, j - 1); }   // Function to print the array static void printArray(int[] arr, int size) {     int i;     for(i = 0; i < size; i++)         Console.Write(arr[i] + " ");               Console.WriteLine(); }       // Driver code     public static void Main()      {     int[] arr = { 6, 8, 9, 4, 12, 1 };     int n = arr.Length;       // Function Call     slow_sort(arr, 0, n - 1);       // Print the sorted array     printArray(arr, n);     } }   // this code is contributed by sanjoy_62.

## Javascript

 

Output:

1 4 6 8 9 12

Best Case Time Complexity: , where e > 0
Average Case Time Complexity:
Auxiliary Space: O(1)

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