Quicksort
Implement quicksort and return a sorted list.
Count inversions lite
Implement a function that counts inversions in a list of numbers efficiently.
Bubble Sort
Implement bubble sort that sorts a list of numbers in ascending order.
Selection Sort Implementation
Implement selection sort to sort a list of numbers in ascending order.
Merge Sort
Implement merge_sort(numbers) that returns a sorted copy of the input list using the merge sort algorithm.
Heap Sort Implementation
Implement the heap sort algorithm to sort a list of comparable elements in non-decreasing order.
Radix Sort
Implement LSD radix sort to sort a list of non-negative integers in ascending order.
Bucket Sort
Implement bucket sort to sort a list of floating-point numbers in the range [0,1).
Shell Sort
Implement Shell sort, an in-place comparison sort that generalizes insertion sort, using a gap sequence that shrinks by half each pass.
Reconstruct Itinerary
Given a list of airline tickets, reconstruct the itinerary in order using each ticket exactly once, choosing the lexicographically smallest path when multiple options exist.
K Closest Elements
Implement a function to return the k closest elements to a target in a sorted array.
Merge Two Sorted Lists
Write a function that merges two sorted lists into a single sorted list.
Merge time intervals
Given a list of time intervals, merge all overlapping intervals and return the merged intervals.
Top N per group
Implement top_n_per_group that returns the top N scores for each group from a list of (group, score) pairs.
Argsort Indices
Implement a function that returns the indices that would sort a list of integers, with ties broken by original order.
Merge K Sorted Lists
Write a function that merges multiple sorted lists into a single sorted list.
Accounts Merge
Given a list of accounts, merge those that share any email and return sorted accounts.
Showing 1–17 of 17 challenges · Data Structures & Algorithms
Data Structures & Algorithms — Python coding challenges
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This page lists data structures & algorithms challenges — real Python problems you solve in the browser IDE with instant test feedback. Each challenge includes a clear brief, starter code, and automated checks.
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Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.