Coding Interview Questions

⏱ 5 min read Dynamic programming on strings is one of the most important and frequently tested DP categories. The pattern is consistent: define […] Read article

⏱ 6 min read Graph problems appear in 20% of coding interviews at top tech companies. The key challenge is recognizing that a problem Read article

⏱ 5 min read Array problems are the most common category in coding interviews, appearing in over 40% of questions. This guide organizes array Read article

⏱ 6 min read String problems appear in 25-30% of coding interviews, making them the second most common category after arrays. String manipulation requires Read article

⏱ 6 min read Beyond the standard DP patterns (knapsack, LCS, linear), advanced DP techniques solve problems that seem intractable at first glance. Bitmask Read article

⏱ 6 min read Beyond basic DFS traversal, advanced DFS patterns solve graph structure problems: finding cycles, identifying critical nodes and edges, and decomposing Read article

⏱ 7 min read Beyond basic BFS/DFS, advanced graph algorithms solve optimization problems: finding the cheapest path with constraints, detecting negative cycles, computing all-pairs Read article

⏱ 7 min read System design interviews have a high failure rate — not because the problems are impossible, but because candidates make predictable Read article

⏱ 5 min read Back-of-envelope estimation is expected in every system design interview. Having key numbers memorized — latency, throughput, storage sizes, and powers Read article

⏱ 7 min read Math-based problems appear in approximately 10% of coding interviews and are often considered the hardest category because the solutions require Read article

⏱ 5 min read Stacks and queues are fundamental data structures that appear in 15-20% of coding interviews. The stack (LIFO) is essential for Read article

⏱ 7 min read Grid and matrix problems are graph problems in disguise. Each cell is a node; adjacent cells (up, down, left, right) Read article

⏱ 7 min read Beyond the classic Gang of Four patterns, several design patterns appear frequently in object-oriented design interviews and production code. This Read article

⏱ 7 min read The sweep line technique processes events in sorted order along a dimension (typically time or position). It converts 2D problems Read article

⏱ 7 min read Topological sort orders vertices in a directed acyclic graph (DAG) such that for every edge (u, v), u appears before Read article