Binary search
Return the index of target in a sorted list, or -1 if not present.
BFS level-order traversal
Return the level-order traversal of a binary tree as a list of lists.
Longest increasing subsequence
Return the length of the longest strictly increasing subsequence.
Find Peak Element
Implement a function that returns the index of any peak element in an integer array.
Median of Two Sorted Arrays
Given two sorted arrays, return the median of the combined sorted array in O(log(min(n,m))) time.
Path Sum II All Paths
Return all root-to-leaf paths where the sum of node values equals a target.
Shortest Path in Binary Matrix
Implement BFS to find the shortest path length from (0,0) to (n-1,n-1) in an n x n binary matrix, moving through 0 cells in 8 directions.
K Closest Elements
Implement a function to return the k closest elements to a target in a sorted array.
Level Order Traversal
Implement a function that performs a level order traversal of a binary tree and returns node values as a list of lists.
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.
Largest Area Histogram Matrix
Given a binary matrix, compute the largest rectangle area consisting entirely of 1s.
Showing 1–11 of 11 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.