7 min read As of October 2026: which paid interview-prep mocks, cohorts and question banks are worth it for a working engineer, what each costs, and when the free route does the job. Read article
7 min read A reference to the main dynamic programming families, what the dp array means in each, and the canonical problems that drill each one. Read article
5 min read The classic n-pairs parentheses problem, why the brute-force filter is a trap, and the pruning rule that keeps backtracking clean. Read article
6 min read Walking Minimum Window Substring from the brute-force baseline to the O(n) sliding window that tracks coverage with a single counter. Read article
6 min read A walkthrough of LeetCode 72, from the recursive prefix idea to the 2D table, its O(n)-space version, and the follow-ups interviewers ask. Read article
7 min read House Robber reduces to two running numbers and a two-state machine, and that same shape solves the circular, tree, and stock-cooldown follow-ups. Read article
6 min read Kadane’s algorithm finds the largest contiguous subarray sum in a single pass, and the interview really lives in the follow-ups: all-negative inputs, returning indices, and the product and circular variants. Read article
7 min read Why 3Sum sorts first, where the duplicate skips go, and what interviewers ask once your two-pointer solution compiles. Read article
6 min read A practical comparison of LeetCode Premium and AlgoExpert, and who each one is actually right for. Read article
6 min read Word Break looks like a string problem but rewards you for caching subproblems by start index, from the memoized recursion to the trie follow-up. Read article
5 min read The no-division array question rewards a prefix-and-suffix pass, and the O(1) space follow-up is where most candidates stumble. Read article
6 min read The two-pointer window that turns a quadratic substring scan into one linear pass, plus the stale-index guard that quietly breaks the fast version. Read article
5 min read The balanced-brackets question is a stack in disguise, and the same move carries straight into Min Stack and Decode String. Read article
5 min read Greedy returns the wrong coin count the moment denominations aren’t standard, so Coin Change needs a short dynamic-programming table instead. Read article
6 min read How to size a coding interview prep schedule to the weeks and hours you actually have, and what to cut when the week falls apart. Read article
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