Let's take the input array as {15, 3, 12, 6, -9, 9, 0} and we can see how the Quick sort is sorting the array.
- Choose the lowest or highest index value as a pivot element, in our above example we chose the lowest index as a pivot element 15.
- Declare two variables (i.e. pointer) to store the lowest and highest index position except the pivot element, so the lowest index position is 1 points the value 3 and the highest index position is 6 which is pointing the value 0
- Move the left side pointer towards right until the value of the pointer is less than or equal to the pivot element.
- Move the right side pointer towards left until the value of the pointer is greater than the pivot element.
- Interchange the values of left side pointer and right side pointer.
- Interchange the values of leftmost index (i.e. position 0 has the pivot element 15) and right side pointer.
- The right side pointer is a new pivot position for the value 15
- Split the array into two sub-arrays with the help of pivot point
- Index from 0 to pivot
- Index from (pivot + 1) to (n - 1), where n is the length of an array
- Apply the step 1 to 8 until there is no more elements to split as an array.