writings by quantinium — programming, systems, and other things. https://quantinium.dev This is an overview about different software licenses that one can choose on various platforms that define how their software must be used by some other party. https://quantinium.dev/blog/learning-about-different-software-licenses https://quantinium.dev/blog/learning-about-different-software-licenses Wed, 11 Nov 2026 00:00:00 GMT Learning about singly and doubly linked lists, the dummy node trick, reversal, fast and slow pointers for middles, cycles and nth-from-end, merging and sorting lists, and hash map plus doubly linked list designs like LRU cache, with leetcode questions for practice. https://quantinium.dev/learnings/dsa_linked-lists https://quantinium.dev/learnings/dsa_linked-lists Mon, 14 Sep 2026 00:00:00 GMT Learning about topological ordering of DAGs using Kahn's algorithm and DFS reverse postorder, along with cycle detection in directed graphs, with leetcode questions for practice. https://quantinium.dev/learnings/dsa_topological-sort https://quantinium.dev/learnings/dsa_topological-sort Sun, 13 Sep 2026 00:00:00 GMT Learning the ordering invariant, operations, and applications of Binary Search Trees. https://quantinium.dev/learnings/dsa_binary-search-trees https://quantinium.dev/learnings/dsa_binary-search-trees Sat, 05 Sep 2026 00:00:00 GMT Learning about Binary Trees https://quantinium.dev/learnings/dsa_binary-trees https://quantinium.dev/learnings/dsa_binary-trees Sat, 05 Sep 2026 00:00:00 GMT Learning about graph terminology, directed and undirected graphs, weighted and unweighted graphs, and the adjacency matrix, adjacency list and edge list representations. https://quantinium.dev/learnings/dsa_graphs https://quantinium.dev/learnings/dsa_graphs Sat, 05 Sep 2026 00:00:00 GMT Learning about Trees, Searching algorithms such as BFS and DFS and Tree Traversal techniques such as In-order, Pre-order, Post-order. https://quantinium.dev/learnings/dsa_trees-traversal-algorithms https://quantinium.dev/learnings/dsa_trees-traversal-algorithms Wed, 02 Sep 2026 00:00:00 GMT Learning about row major layout and cache behaviour, flat indexing, direction arrays, spiral and diagonal orders, in-place rotation, using the matrix as its own scratch space, staircase search, and treating a grid as a graph with leetcode questions for practice. https://quantinium.dev/learnings/dsa_matrix-traversal https://quantinium.dev/learnings/dsa_matrix-traversal Mon, 31 Aug 2026 00:00:00 GMT Learning about stack frames, recursion depth limits, the recursion tree and complexity, tail calls, converting recursion to an explicit stack, and memoization with leetcode questions for practice. https://quantinium.dev/learnings/dsa_recursion-and-the-call-stack https://quantinium.dev/learnings/dsa_recursion-and-the-call-stack Sun, 30 Aug 2026 00:00:00 GMT Learning about the cost model of strings, frequency vectors as window state, bytes vs characters, and rolling hashes for O(1) substring comparison with leetcode questions for practice. https://quantinium.dev/learnings/dsa_string-manipulation-and-matching https://quantinium.dev/learnings/dsa_string-manipulation-and-matching Sat, 29 Aug 2026 00:00:00 GMT A deep dive into docker covering images, dockerfiles, multi-stage builds and docker compose. https://quantinium.dev/blog/containerization-deep-dive https://quantinium.dev/blog/containerization-deep-dive Sat, 22 Aug 2026 00:00:00 GMT Learning about hash functions, collision resolution, load factor/resizing, and designing a hash map and LRU cache from scratch with leetcode questions for practice. https://quantinium.dev/learnings/dsa_hashing https://quantinium.dev/learnings/dsa_hashing Fri, 21 Aug 2026 00:00:00 GMT Learning about comparison-based and non-comparison sorting algorithms with leetcode questions for practice. https://quantinium.dev/learnings/dsa_sorting https://quantinium.dev/learnings/dsa_sorting Fri, 21 Aug 2026 00:00:00 GMT Learning about binary search on sorted arrays and binary search on answer with leetcode questions for practice. https://quantinium.dev/learnings/dsa_binary-search https://quantinium.dev/learnings/dsa_binary-search Wed, 19 Aug 2026 00:00:00 GMT A deep dive into how VMs, containers, and isolates achieve isolation, and the tradeoffs of each. https://quantinium.dev/learnings/devops_virtual-machines-containers-isolates https://quantinium.dev/learnings/devops_virtual-machines-containers-isolates Tue, 18 Aug 2026 00:00:00 GMT Learning about prefix, suffix and difference arrays. https://quantinium.dev/learnings/dsa_prefix-suffix-difference-arrays https://quantinium.dev/learnings/dsa_prefix-suffix-difference-arrays Mon, 17 Aug 2026 00:00:00 GMT Learning about sliding window technique and leetcode questions. https://quantinium.dev/learnings/dsa_sliding-window https://quantinium.dev/learnings/dsa_sliding-window Sun, 16 Aug 2026 00:00:00 GMT Learning about arrays, two pointer approach and cyclic sort pattern with some leetcode questions for practice. https://quantinium.dev/learnings/dsa_array-two-pointer-cyclic-sort https://quantinium.dev/learnings/dsa_array-two-pointer-cyclic-sort Sat, 15 Aug 2026 00:00:00 GMT A guide to running a WireGuard VPN and Pi-hole DNS filtering on a VPS. https://quantinium.dev/blog/setting-up-wireguard-and-pihole https://quantinium.dev/blog/setting-up-wireguard-and-pihole Tue, 23 Jun 2026 00:00:00 GMT A guide to setting up continuous deployment on a vps https://quantinium.dev/blog/deploying-software-on-a-vps https://quantinium.dev/blog/deploying-software-on-a-vps Fri, 13 Mar 2026 00:00:00 GMT A guide to deploy a backend server to a digitalocean droplet running nixos. https://quantinium.dev/blog/deploying-applications-on-nixos-vps https://quantinium.dev/blog/deploying-applications-on-nixos-vps Mon, 21 Jul 2025 00:00:00 GMT A guide to install nixos on a vps, deploying configuration using deploy-rs and managing secrets using sops-nix https://quantinium.dev/blog/installing-and-managing-a-linux-vps https://quantinium.dev/blog/installing-and-managing-a-linux-vps Sat, 19 Jul 2025 00:00:00 GMT