I'm a freshman majoring in Computer Science, currently growing along two main tracks:
-
Competitive Programming & Algorithmic Thinking
I use problem solving as my main training ground, focusing on C++, data structures, dynamic programming, graph algorithms, search, greedy methods, and implementation skills. -
AI-assisted Software Building
I am also exploring how to turn ideas into usable projects with modern web technologies and AI coding tools, especially through small front-end experiments built with React and TypeScript.
This GitHub profile is my long-term technical journal: part coding archive, part blog index, part record of how I grow from solving problems to building real things.
| Track | What I'm working on |
|---|---|
| Competitive Programming | C++ / AtCoder / Codeforces / Luogu |
| Algorithm Notes | Problem reviews and reusable solution patterns |
| AI-assisted Development | Learning to build small web projects with AI tools |
| Technical Writing | Recording mistakes, ideas and solution structures |
Browser-based real-time 3D rendering and hand gesture recognition for an immersive, photo-integrated holiday experience.
Live Demo: christmas-tree-phi-seven.vercel.app
Repository: github.com/your-username/gesture-christmas-tree
Demo Video: Watch on Bilibili
Stack: React · TypeScript · Three.js · @mediapipe/hands · Zustand
Gesture 3D Christmas Tree combines real-time 3D particle rendering, AI-powered hand tracking, and photo-integrated visual storytelling. Users can upload personal images and seamlessly control the scene's state—clustering particles into a structured tree, scattering them into an exploded field, or focusing on central photos—entirely through natural hand gestures.
Browser-based whiteboard recording for teaching, technical explanation and presentation videos.
Live Demo: canvascast.nine19een.com
Repository: github.com/nine19een/CanvasCast
Demo Video: Watch on Bilibili
Stack: React · TypeScript · Vite · SVG · MediaRecorder API
CanvasCast combines whiteboard drawing, slide-based presentation, custom recording frames, camera overlay, microphone selection, teleprompter and browser-based recording output into one lightweight web app.
Video-only workflow for generating grounded lecture handouts from public course videos.
Repository: github.com/nine19een/lecture-video-handout-workflow
Stack: Python · yt-dlp · FFmpeg · Pillow · PyYAML · faster-whisper · Markdown/JSONL
Lecture Video Handout Workflow turns public lecture videos into traceable artifacts and learner-facing Chinese handouts through an agent-assisted workflow, emphasizing validation over black-box summarization.
I write technical posts about algorithm problems I have solved, focusing not only on accepted code, but also on the thinking process, mistakes, patterns, and reusable ideas behind the solution.
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📑 蓝桥杯 2026 省赛 B 组复盘：考前状态、考场决策与赛后重做
A post-contest review of my Lanqiao Cup 2026 Provincial Round. -
📑 组合数学专题总结
Modular inverse recurrence, factorial precomputation, derangements, binomial coefficients, and Catalan numbers via the reflection method. -
📑 洛谷 P1637 / SPOJ SP2815 INCSEQ 复盘：长度 k 严格上升子序列的树状数组模板
Layered DP and Fenwick Tree for counting increasing subsequences. -
📑 Codeforces 1065-C1/C2 复盘：XOR 博弈与最高有效位
XOR games and the role of the most significant bit. -
📑 洛谷 P1133 复盘：从线性 DP 到破环成链
From flawed linear DP to standard ring-to-chain DP. -
📑 AtCoder ABC455-E 复盘：前缀差值统计与三集合容斥
Prefix-difference states and inclusion-exclusion for substring counting.
I use competitive programming as my main way to train algorithmic thinking, coding stability and problem decomposition.
- 🥇 Lanqiao Cup Provincial First Prize, 2026
蓝桥杯省赛一等奖 · C/C++ 程序设计大学 B 组 · 北京赛区
Ranked 25th in Beijing Division, approximately top 1.4% based on 179 first-prize winners.
I use online contests to test my current problem-solving ability under time pressure.
This section records my contest history across AtCoder, Codeforces, Lanqiao and other platforms.
I keep the full table here as a long-term archive of my progress, including solved count, rank, rating change and submission links when available.
📘 Full Contest History
This is the archive of my daily problem-solving practice.
The full table is intentionally folded to keep the profile readable while preserving the complete record.
🚀 Full Coding Practice Log
- Blog: nine19een.com
- Email: nine19eenowo@gmail.com