Quick Sort || O(nlogn) Time complexity || O(1) space Complexity |

#include<iostream>
#include<cmath>
#include<vector>
using namespace std;

//Ascending Order ||

int find(int arr[] , int low, int high){
  int i = low;
  int j = high;
  int pivot = arr[low];
  while(i<j){
    while(pivot>=arr[i] && i<=high){
      i++;
    }
    while(pivot<arr[j] && j>=low){
      j--;
    }
    if(i<j){
    swap(arr[i],arr[j]);
    }
  }
  swap(arr[low],arr[j]);
  return j;
}
void QS(int arr[],int low ,int high){
  if(low<high){
    int partition = find(arr,low,high);
    QS(arr,low,partition-1);
    QS(arr,partition+1,high);
  }
}
int main(){
  int arr[]={5,100,3,56,0,1};
  int size = 6;
  QS(arr,0,size-1);
  for(int i=0; i<7; i++){
    cout<<arr[i]<<" ";
  }
  return 0;
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#include<iostream>
#include<cmath>
#include<vector>
using namespace std;

//Ascending Order ||

int find(int arr[] , int low, int high){
  int i = low;
  int j = high;
  int pivot = arr[low];
  while(i<j){
    while(pivot<=arr[i] && i<=high){
      i++;
    }
    while(pivot>arr[j] && j>=low){
      j--;
    }
    if(i<j){
    swap(arr[i],arr[j]);
    }
  }
  swap(arr[low],arr[j]);
  return j;
}
void QS(int arr[],int low ,int high){
  if(low<high){
    int partition = find(arr,low,high);
    QS(arr,low,partition-1);
    QS(arr,partition+1,high);
  }
}
int main(){
  int arr[]={5,100,3,56,0,1};
  int size = 6;
  QS(arr,0,size-1);
  for(int i=0; i<7; i++){
    cout<<arr[i]<<" ";
  }
  return 0;