After upgrading my application to Next.js 15 (Release Candidate / Stable) and React 19, my dynamic routing pages crashed with the runtime error: Error: Route "/blog/[slug]" used `params.slug`. `params` should be awaited before ...Read more
We are building a distributed task build engine (similar to Bazel or Make) that resolves dependency trees across 500,000 code packages. Textbooks teach both Kahn’s algorithm (indegree BFS) and DFS post-order reversal. Why do production build systems almost universally prefer Kahn’s ...Read more
When elements in an array appear twice except one, we can simply XOR all numbers together. But what if every element appears three times, except for a single number that appears once? The standard hash-map solution uses O(N) space. How can ...Read more
Given an array of integers nums and an integer k, return the total number of subarrays whose sum equals k. Many people try to use a Sliding Window / Two Pointers approach, but it fails whenever the array contains negative numbers. ...Read more
In standard coding questions, Lowest Common Ancestor (LCA) in a binary tree is solved with post-order recursive DFS in O(N) time. But in production systems (like corporate organization charts or Git commit graph merges), we need to answer thousands of ...Read more
Given a characters array tasks representing the tasks a CPU needs to do, and a cooldown integer n, each task takes 1 CPU interval. Identical tasks must be separated by at least n cooldown intervals. Most people simulate this using a ...Read more
In our telemetry service, financial tick prices arrive at ~10,000 events/second. We need an online algorithm that can output the exact running median at any moment. Sorting the buffer on every tick is O(N log N), which is impossible at high ...Read more