From 0 to 1 Data Structures & Algorithms in Java - Heap Sort Phase II - The Actual Sort

The video tutorial explains the process of heapifying an unsorted array and implementing heap sort. It covers helper methods for heap operations, such as calculating child and parent indices and swapping elements. The percolate down method is detailed, showing how it maintains the heap property. The tutorial then demonstrates the two phases of heap sort: heapifying the array and transforming it into a sorted array. Finally, it discusses the code for heapsort and analyzes its time and space complexity.

What is the formula to find the left child index in a heap implemented using an array?

• 2 * index + 1

• index / 2

• 2 * index

• index - 1

What is the formula to find the right child index in a heap implemented using an array?

• 2 * index + 2

• index / 2 + 1

• index - 2

• 2 * index

What is the purpose of the percolate down method in a heap?

• To move an element to the correct position within the heap

• To find the maximum element in the heap

• To swap the root with the last element

• To calculate the height of the heap

What is the main difference between percolate down and sift down?

• Sift down is used for min-heaps

• Percolate down is faster

• There is no difference; they are interchangeable terms

• Percolate down is used for max-heaps

During the heapify process, from which node do we start percolating down?

• The root node

• The last leaf node

• The parent of the last leaf node

• The node with the smallest value

In the heap sort process, what happens to the largest element in the heap?

• It is left unchanged

• It is swapped with the last element and moved to the sorted portion

• It is removed from the heap

• It is moved to the beginning of the array

What is the first step in the heap sort process?

• Heapify the unsorted array

• Find the maximum element

• Sort the array using quicksort

• Divide the array into two halves

What is the time complexity of heap sort?

• O(n)

• O(log n)

• O(n log n)

• O(n^2)

Which of the following is NOT a property of heap sort?

• It has a space complexity of O(1)

• It is not a stable sort

• It sorts in place

• It is an adaptive sort

Why is heap sort not considered a stable sort?

• It only works on arrays

• It is slower than other sorting algorithms

• It requires additional space

• It does not maintain the relative order of equal elements