# What Is a Quick Sort in Data Structure?

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Scott Campbell

What Is a Quick Sort in Data Structure?

Data structure is an essential concept in computer science, and one of the most commonly used sorting algorithms is the quick sort. The quick sort algorithm, also known as partition-exchange sort, is an efficient and widely used sorting algorithm that can sort a list or an array of elements in ascending or descending order.

## How Does Quick Sort Work?

The quick sort algorithm follows the divide-and-conquer strategy to sort the elements. It works by selecting a pivot element from the array and partitioning the other elements into two sub-arrays, according to whether they are less than or greater than the pivot. The pivot can be chosen in different ways, such as selecting the first element, last element, or even a random element from the array.

The partitioning process involves rearranging the elements around the pivot so that all elements smaller than the pivot are placed before it, and all elements greater than the pivot are placed after it. This step ensures that the pivot is in its final sorted position.

Once the pivot is in its correct position, we recursively apply the same steps to both sub-arrays created by partitioning. This process continues until each sub-array contains only one element or becomes empty. Finally, when all sub-arrays have been sorted independently, we combine them to obtain a fully sorted array.

## The Steps of Quick Sort:

1. Select a pivot element from the array.
2. Partition the other elements into two sub-arrays based on their relation to the pivot.
3. Recursively apply steps 1 and 2 to each sub-array created by partitioning.
4. Combine all sorted sub-arrays to obtain a fully sorted array.

• Efficiency: Quick sort is known for its efficiency and can be one of the fastest sorting algorithms when implemented correctly.
• Space Complexity: Quick sort has a space complexity of O(log n) on average, making it an efficient choice for large datasets.
• In-Place Sorting: The partitioning process involved in quick sort allows it to sort the elements in-place, without requiring additional memory.