Valid parentheses
Return True if brackets in the string close in the correct order.
Binary search
Return the index of target in a sorted list, or -1 if not present.
Index of peak element
Implement a function that returns the index of any peak element in a given integer array.
Count pairs with given difference
Count how many unordered pairs in a list have a given absolute difference using an efficient approach.
Previous Smaller Element
Find the nearest previous index with a smaller value for every element in an array.
Pascal Triangle Row
Given a non-negative integer n, return the nth row of Pascal's triangle as a list of integers.
Employee Hierarchy
Build an employee hierarchy tree and compute the total number of direct and indirect reports for each employee.
Union Find Class
Implement a UnionFind class with find and union operations supporting path compression and union by size.
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.
Shell Sort
Implement Shell sort, an in-place comparison sort that generalizes insertion sort, using a gap sequence that shrinks by half each pass.
Exponential Search
Implement exponential search to find any valid index of a target in a sorted list.
Find Peak Index
Given a list of integers, return the index of any peak element where the value is not smaller than its neighbors.
Peak Element in Array
Implement a function that returns the index of any peak element in a list of integers.
Merge Two Sorted Lists
Write a function that merges two sorted lists into a single sorted list.
Jump Search
Implement the jump search algorithm to locate a target in a sorted list, returning its index or -1.
Delete Old Records
Filter a list of records by removing those with a date older than a given cutoff date.
Consecutive available seats
Given a list of seat statuses, return the length of the longest consecutive run of available (0) seats.
Argsort Indices
Implement a function that returns the indices that would sort a list of integers, with ties broken by original order.
Lowest Common Ancestor in a Binary Search Tree
Implement a function to find the lowest common ancestor of two node values in a binary search tree.
Memory view slice
Implement chunk_list that splits a list into consecutive sublists of a given chunk size.
Employees earning more than manager
Given employee records with manager IDs, find those who earn more than their direct manager.
Showing 1–22 of 22 challenges · easy · 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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