Which sorting algorithm operates by selecting a pivot and moving elements left or right of it?

Which sorting algorithm operates by selecting a pivot and moving elements left or right of it?

• A. Binary Search
• B. Quick Sort
• C. Bubble Sort
• D. Merge Sort

Answer: (B)

This item tests a sorting approach that uses a pivot to split the data. You pick a pivot element, move items smaller than the pivot to one side and items larger to the other, then apply the same partitioning process to each side. That pattern—pivot, partition, then recursively sort the partitions—is the hallmark of Quick Sort. It often sorts in place and has an average time complexity of O(n log n), though a bad pivot can degrade to O(n^2). Binary Search is about locating a value within a sorted array by repeatedly comparing to the middle element and narrowing the search space, not reordering elements. Bubble Sort sorts by swapping adjacent elements step by step, with no single pivot guiding a partition. Merge Sort divides the list into halves and merges sorted halves, which is a divide-and-conquer approach that doesn’t rely on partitioning around a pivot. So the pivot-based partitioning described here points to Quick Sort.

This item tests a sorting approach that uses a pivot to split the data. You pick a pivot element, move items smaller than the pivot to one side and items larger to the other, then apply the same partitioning process to each side. That pattern—pivot, partition, then recursively sort the partitions—is the hallmark of Quick Sort. It often sorts in place and has an average time complexity of O(n log n), though a bad pivot can degrade to O(n^2).

Binary Search is about locating a value within a sorted array by repeatedly comparing to the middle element and narrowing the search space, not reordering elements. Bubble Sort sorts by swapping adjacent elements step by step, with no single pivot guiding a partition. Merge Sort divides the list into halves and merges sorted halves, which is a divide-and-conquer approach that doesn’t rely on partitioning around a pivot. So the pivot-based partitioning described here points to Quick Sort.