Python: Sort an unsorted array numbers using Wiggle sort

Last update on April 23 2025 12:50:09 (UTC/GMT +8 hours)

24. Wiggle Sort

Write a Python program to sort an unsorted array of numbers using Wiggle sort.

Wiggle Sort:
Given an unsorted array nums, reorder it in-place such that nums[0] <= nums[1] >= nums[2] <= nums[3]....
For example, given nums = [3, 5, 2, 1, 6, 4], one possible answer is [1, 6, 2, 5, 3, 4].

Sample Solution:

Python Code:

def wiggle_sort(arra_nums):
    for i, _ in enumerate(arra_nums):
        if (i % 2 == 1) == (arra_nums[i - 1] > arra_nums[i]):
            arra_nums[i - 1], arra_nums[i] = arra_nums[i], arra_nums[i - 1]

    return arra_nums

print("Input the array elements: ")
arra_nums = list(map(int, input().split()))
print("Original unsorted array:")
print(arra_nums)
print("The said array after applying Wiggle sort:")
print(wiggle_sort(arra_nums))

Sample Output:

Input the array elements: 
 1 5 2 3 4 6
Original unsorted array:
[1, 5, 2, 3, 4, 6]
The said array after applying Wiggle sort:
[1, 5, 2, 4, 3, 6]

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python program to implement wiggle sort on an unsorted array and then verify the pattern nums[0] ≤ nums[1] ≥ nums[2] ≤ ... holds.
Write a Python script to rearrange a list into wiggle order and then output the transformed list along with validation of the pattern.
Write a Python program to use wiggle sort on a list of integers and then count the number of positions where the condition is satisfied.
Write a Python function to implement an in-place wiggle sort and then print the list before and after sorting.

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