Find the n-th Fibonacci number with a recursive function in Python. Clear problem statement, examples, easy-to-grasp intuition, commented code, dry…

Learn two easy ways to test a Palindrome String: a clean recursive method and a space saving two-pointer loop. Includes…

Learn how to detect cycle in a directed graph with Kahn’s algorithm. Simple intuition, commented Python code, step-by-step dry run,…

Learn how to perform topological sorting of a DAG using Kahn’s algorithm (BFS based). Clear steps, commented Python code, dry-run…

See how to solve “detect cycle in a directed graph” using depth-first search and two helper arrays. Simple idea, commented…

Learn how to find a topological sort of a directed acyclic graph (DAG) using depth-first search (DFS) and a stack.…

Learn how to test if an undirected graph is bipartite by coloring it with two colors. Simple DFS idea, commented…

Learn how to count the number of distinct islands shape in a binary grid using DFS and shape hashing. Clear…

Learn how to count the number of islands (leetcode 200) in a 2-D grid using both Breadth-First Search (BFS) and…

Learn how to find all shortest paths (Word Ladder II) from one word to another by changing one letter at…