// coding-interview-questions
Real coding questions, worked solutions, and the patterns behind them.
7 min read Stock trading dynamic programming problems are a classic interview cluster. Every variant – one transaction, unlimited, at most k, cooldown, […] Read article
9 min read What is Interval DP? Interval DP is a dynamic programming pattern where you optimize over all sub-intervals of a range. Read article
10 min read 2D DP Pattern Overview 2D dynamic programming problems use a 2D table where dp[i][j] represents the optimal value considering only Read article
10 min read Advanced Heap Interview Patterns Heaps appear in a surprising number of interview problems beyond the simple “find the Kth largest Read article
9 min read Graph Traversal Interview Patterns Graph problems appear in nearly every senior engineering interview. The key is recognizing which traversal fits Read article
9 min read Dynamic Programming on Strings Interview Patterns String DP problems share a common structure: a 2D table where one dimension indexes Read article
10 min read Linked list problems trip up candidates because pointer manipulation is easy to mess up under pressure. These patterns cover every Read article
10 min read Sorting problems appear constantly in interviews – not just “implement merge sort” but as tools to simplify harder problems. Master Read article
8 min read When Greedy Works: The Exchange Argument Greedy algorithms make the locally optimal choice at each step. They are provably correct Read article
10 min read Strings appear in roughly 25-30% of coding interviews. Unlike arrays or trees, string problems have a concentrated set of patterns Read article
9 min read Trie (prefix tree) problems appear frequently in coding interviews. This guide covers the core patterns with Python implementations you can Read article
10 min read Range query problems appear frequently in competitive programming and technical interviews. Knowing which data structure to reach for – and Read article
8 min read Monotonic Deque Pattern – Sliding Window Maximum LeetCode 239. Given an array and window size k, return the maximum in Read article
7 min read Core Probability Concepts Probability questions test your ability to reason about uncertainty and expected behavior. Three concepts appear repeatedly in Read article
5 min read The Two-Eggs (Light Bulbs) Problem: 80-Floor Building, Optimal Strategy, and DP “You have 2 eggs and a 100-floor building. Find Read article
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