int pivot = arr[start];

int count = 0;

for(int i = start + 1; i <= end; i++){

if(arr[i] <= pivot){

count++;

}

}

int pivotIndex = start + count;

swap(arr[pivotIndex], arr[start]);

int i = start ;

int j = end;

while(i < pivotIndex && j > pivotIndex){

while(arr[i] <= pivot){

i++;

}

while(arr[j] > pivot){

j--;

}

if(i < pivotIndex && j > pivotIndex){

swap(arr[i], arr[j]);

i++;

j--;

}

}

return pivotIndex;

if(start >= end){

return;

}

int p = partition(arr,start, end);

quicksort(arr, start, p-1);

quicksort(arr, p+1, end);

int arr[] = {10,9,8,7,6,5,4,3,2,1};

int n = sizeof(arr)/sizeof(arr[0]);

quicksort(arr, 0, n-1);

for(int i = 0; i < n; i++){

cout << arr[i] << " ";

}

cout << endl;

return 0;

}