During deep learning training in PyTorch 2.x, my script crashed midway through an epoch with the error: RuntimeError: CUDA out of memory. Tried to allocate 512.00 MiB (GPU 0; 23.69 GiB total capacity; ...Read more
RTSALL Latest Questions
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
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
In Floyd’s Cycle-Finding Algorithm (Tortoise and Hare), slow moves by 1 step and fast moves by 2 steps. If a cycle exists, they are guaranteed to meet. Then comes part 2: to find the start of the cycle (the loop origin), ...Read more
We are building an autonomous drone route planner that must visit N = 20 delivery drop points with minimum total travel distance. Brute-force testing all permutations is (N - 1)!. For N = 20, $19! pprox 1.21 imes 10^{17}$, which would ...Read more
Given an integer array, we need to find two numbers whose bitwise XOR (A ^ B) is maximized. The brute force approach tests all pairs in O(N^2), which is way too slow when N = 100,000. People recommend building a Binary ...Read more
In low-level systems programming and coding interviews, people always use the expression n & (n - 1) to count set bits (Hamming Weight) or check if a number is a power of 2. I know it works, but what is the ...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