How to sort 0,1 in an Array without using any extra space using C#?

Take two-pointers, low, high. We will use low pointers at the start, and the high pointer will point at the end of the given array.

If array [low] =0, then no swapping required

If array [low] = 1, then swapping is required. Decrement high pointer once.

Time complexity − O(N)

Example

 Live Demo

using System; namespace ConsoleApplication{    public class Arrays{       public void SwapZerosOnes(int[] arr){          int low = 0;          int high = arr.Length - 1;          while (low < high){             if (arr[low] == 1){                Swap(arr, low, high);                high--;             }             else{                low++;             }          }       }       private void Swap(int[] arr, int pos1, int pos2){          int temp = arr[pos1];          arr[pos1] = arr[pos2];          arr[pos2] = temp;       }    }    class Program{       static void Main(string[] args){          Arrays a = new Arrays();          int[] arr1 = { 0, 1, 1, 0, 1, 1 };          a.SwapZerosOnes(arr1);          for (int i = 0; i < arr1.Length; i++){             Console.WriteLine(arr1[i]);          }       }    } }

Output

0 0 1 1 1 1