Archives

A collection of original AtCoder writeups from March to June 2024, covering ABC 340 F, 341 D, 346 D/E/F, and 356 D/E/F.

A collection of original AtCoder writeups from April to July 2024, covering ABC 348 E/F, 350 D/E, 351 D/E/F, 357 D/E/F, 358 C/E/G, and 360 E.

A collection of original Codeforces writeups from January to July 2024, focused on constructive problems, bit operations, and greedy techniques.

A collection of original Codeforces writeups from December 2023 to July 2024, focused on prefix sums, strings, and problem-solving transformations.

A collection of original Codeforces writeups from January to September 2024, focused on number theory, games, combinatorics, and EDU problems.

A collection of original writeups covering the Zhengzhou Invitational, Kunming Invitational, HDU 2973, and Luogu B3645.

A collection of original writeups from December 2023 to August 2024, covering bookmarked winter contests, weekly contests, and multi-school problems.

Mindfulness, cognitive training, and a healthy lifestyle may help sharpen your focus.

Based on the original Redis notes, this post keeps the material on distributed locks, message queues, HyperLogLog, and high availability.

Earlier Redis notes originally written in Apple Notes.

Based on the original MySQL notes, this post keeps the material on transactions, locks, MVCC, logs, and optimization.

Earlier MySQL notes originally written in Apple Notes.

Built around the original 'Problem-Setting Syndrome' notes, this post keeps the Magic Bag problem, its derivation, code, and follow-up directions.

Based on the original Java concurrency notes, this post keeps the material on the JMM, locks, atomic classes, ThreadLocal, thread pools, and related topics.

Based on the original MySQL notes, this post keeps the material on fundamentals, indexes, B+ trees, and execution plans.

Built from the original Redis notes and Apple Notes, this post restores cache positioning, data structures, the threading model, and persistence.

Based on the original Java notes, this post keeps the material on collections, IO, reflection, proxies, and SPI.

This post puts operating systems back into context: why programs need processes, threads, virtual memory, page cache, system calls, and file systems.

Don't reduce computer networks to protocol names. Follow a real request and see how DNS, TCP, TLS, HTTP, and congestion control work together.

From convolution and point-value representation to FFT/NTT and formal power series, this post explains what the polynomial toolkit is really solving.

Based on the original number theory notes, this post restores Dirichlet convolution, the Mobius function, inversion techniques, and common identities.

Built from the original notes, this post restores ordinary and exponential generating functions, modeling intuition, and several representative problems.

Based on the original game theory notes, this post restores the decision framework, Bash/Nim, misere play, Fibonacci game, Wythoff game, and the SG function.

Built from the original search problem sets and solution notes, this post organizes DFS, BFS, pruning, shortest paths, and state-space search.

Based on the original number theory notes, this post keeps the material on prime sieves, Euler's totient function, and Wilson's theorem.

Based on the original number theory notes, this post keeps gcd, lcm, Bezout's identity, extended Euclid, fast exponentiation, inverses, and CRT.