Q: What is Bitonic Sort?
A: Bitonic Sort is a parallel sorting algorithm that works by building a bitonic sequence. A bitonic sequence is a sequence that first increases up to a certain index, and then decreases for the rest of the elements.
Q: How does Bitonic Sort work?
A: The algorithm recursively builds a bitonic sequence and then repeatedly splits and merges it until the entire sequence is sorted. It uses a specific property of bitonic sequences to efficiently perform the sorting in a parallel manner.
Q: What is the time complexity of Bitonic Sort?
A: The time complexity of Bitonic Sort is O(log^2(n)) for the parallel version, and O(n log^2(n)) for the serial version. The parallel version is more efficient and can take advantage of parallel processing.
Q: Can Bitonic Sort be used for non-power-of-two-sized arrays?
A: Yes, Bitonic Sort can handle arrays with a length that is not a power of two. However, the array length should be a multiple of 2 for efficient parallelization.
Q: Can you provide an example of Bitonic Sort in Python?
A: Certainly! Here's a simple implementation of the Bitonic Sort algorithm in Python:
def bitonic_sort(arr, up=True):
n = len(arr)
if n <= 1:
return arr
else:
# Bitonic Split
m = n // 2
arr1 = bitonic_sort(arr[:m], True)
arr2 = bitonic_sort(arr[m:], False)
arr = arr1 + arr2
arr = bitonic_merge(arr, up)
return arr
def bitonic_merge(arr, up=True):
n = len(arr)
if n <= 1:
return arr
else:
# Bitonic Merge
bitonic_compare(arr, up)
m = n // 2
arr1 = bitonic_merge(arr[:m], up)
arr2 = bitonic_merge(arr[m:], up)
arr = arr1 + arr2
return arr
def bitonic_compare(arr, up):
m = len(arr) // 2
for i in range(m):
if (arr[i] > arr[i + m]) == up:
# Swap elements to make them in the correct order
arr[i], arr[i + m] = arr[i + m], arr[i]
# Example usage:
arr = [3, 7, 4, 8, 6, 2, 1, 5]
sorted_arr = bitonic_sort(arr)
print("Original Array:", arr)
print("Sorted Array:", sorted_arr)
This Python code demonstrates a simple implementation of the Bitonic Sort algorithm. The bitonic_sort function recursively splits and merges the array, and the bitonic_compare function is used to compare and swap elements in the bitonic sequence. The example array is then sorted using this implementation.
Important Interview Questions and Answers on Bitonic Sort Algorithm
Q: What is Bitonic Sort?
Bitonic Sort is a parallel sorting algorithm that first sorts the input sequence in ascending order and then in descending order, or vice versa. The algorithm recursively builds a bitonic sequence and then merges it.
Q: How does Bitonic Sort work?
Bitonic Sort works by recursively building bitonic sequences and then merging them. In each recursive step, the sequence is divided into two halves, one sorted in ascending order, and the other in descending order. The two halves are then merged to form a bitonic sequence.
Q: Can you explain the key steps of the Bitonic Sort algorithm?
- Bitonic Sequence Construction: Recursively build bitonic sequences.
- Bitonic Merge: Merge two bitonic sequences to form a larger bitonic sequence.
Q: What is the time complexity of Bitonic Sort?
The time complexity of Bitonic Sort is O(log^2(n)).
Q: Provide a simple implementation of Bitonic Sort in Python.
Here is the code.
def bitonic_sort(arr, low, cnt, order):
if cnt > 1:
k = cnt // 2
bitonic_sort(arr, low, k, 1)
bitonic_sort(arr, low + k, k, 0)
bitonic_merge(arr, low, cnt, order)
def bitonic_merge(arr, low, cnt, order):
if cnt > 1:
k = cnt // 2
for i in range(low, low + k):
compare_and_swap(arr, i, i + k, order)
bitonic_merge(arr, low, k, order)
bitonic_merge(arr, low + k, k, order)
def compare_and_swap(arr, i, j, order):
if (arr[i] > arr[j] and order == 1) or (arr[i] < arr[j] and order == 0):
arr[i], arr[j] = arr[j], arr[i]
def bitonic_sort_main(arr):
n = len(arr)
cnt = 1
while cnt < n:
cnt *= 2
bitonic_sort(arr, 0, cnt, 1)
# Example usage:
arr = [3, 7, 4, 8, 6, 2, 1, 5]
bitonic_sort_main(arr)
print("Sorted array:", arr)
This example includes the main sorting function bitonic_sort_main, which takes an array as input and sorts it using the Bitonic Sort algorithm.
