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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.