QuickSort

QuickSort

using System;

namespace QuickSort
{
    public class Program
    {
        public static void Main(string[] args)
        {
            int[] arr = {3, 6, 1, 5, 4};
            
            Console.WriteLine("Input is");
            display(arr);
            
            quickSort(arr);
            
            Console.WriteLine("Output is");
            display(arr);
        }
        
        static void display(int[] arr) {
            foreach (var item in arr) {
                Console.Write(item + " "); 
            }
            
            Console.WriteLine(" ");
        }
        
        static void quickSort(int[] input) {
            quickSort(input, 0, input.Length - 1);
        }
        
        static void quickSort(int[] arr, int left, int right) {
            int index = partition(arr, left, right);
            if (left < index - 1) {
                quickSort(arr, left, index - 1);
            }
            
            if (index < right) {
                quickSort(arr, index, right);
            }
        }
        
        static int partition(int[] arr, int left, int right) {
            int pivot = arr[(left + right) / 2];
            
            while (left <= right) {
            
                while (arr[left] < pivot) {
                    left++;
                }
                
                while (arr[right] > pivot) {
                    right--;
                }
                
                if (left <= right) {
                    int temp = arr[left];
                    arr[left] = arr[right];
                    arr[right] = temp;
                    
                    left++;
                    right--;
                }
            }
            
            return left;
        }
    }
 
}