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
RTSALL Latest Questions
The standard DP solution for Longest Increasing Subsequence (LIS) uses two nested loops: for each element i, scan all previous elements j < i. That takes O(N^2) time, which times out when N = 100,000. Everyone says the optimal solution is ...Read more
In standard textbook explanations of the 0/1 Knapsack problem, the solution uses a 2D table dp[n][W] where each cell represents the max value using a subset of items under capacity W. Then instructors show an optimization: ‘Just replace the 2D array ...Read more
In our embedded C++ runtime, each thread has a strictly limited stack frame (64KB). When traversing deeply skewed binary trees with millions of nodes, recursive DFS triggers a stack overflow, and allocating an explicit heap stack (std::vector) exceeds our device ...Read more
When implementing Dijkstra’s algorithm for large road networks (millions of nodes and edges), the standard textbook approach pushes a new pair (new_dist, u) into a binary heap whenever a shorter path is found. This means old, obsolete distance pairs remain sitting ...Read more
I understand how to solve the Largest Rectangle in Histogram in O(N^2) by expanding left and right from every bar. But top interviewers and competitive programming platforms always expect the O(N) single-pass Monotonic Stack solution. Every explanation I read online just ...Read more
We are building an in-memory session cache for an API gateway handling 50k requests/sec. We need an LRU (Least Recently Used) cache where both get() and put() operations happen strictly in O(1) time. A lot of implementations I see online either ...Read more
We are running a low-latency packet ring buffer service in C++ and Go. Whenever an offset wraps around, we need to rotate a large integer array (up to 10 million elements) by k positions to the right. The standard way people ...Read more