tzyt's Blog

Notes on xv6 Lab 3 page tables, including faster system calls, page-table printing, and detecting accessed pages through RISC-V page-table flags.

Solutions to Codeforces 1703 F and G, covering efficient pair counting and greedy bitwise processing of array operations.

Notes on xv6 Lab 2 system calls, tracing the syscall path and implementing system-call tracing and sysinfo across kernel interfaces.

Solutions to Codeforces 1702 C, D, E, and F, covering position queries, greedy selection, bipartite graph checks, and numeric transformations.

Notes on xv6 Lab 1 utilities, implementing sleep, pingpong, primes, find, and xargs while practicing Unix processes, pipes, and file descriptors.

xv6 operating-system notes on page tables, user and kernel traps, interrupts, context switching, scheduling, and synchronization with locks.

Explains the combinatorial counting solution to Codeforces 1699C by expanding the interval containing successive MEX values in a permutation.

Implements the genetic algorithm from Complexity in C++, covering genome design, fitness evaluation, selection, crossover, and mutation.

Presents a dynamic programming solution to Codeforces 1695C, deciding whether a right-down path through a ±1 grid can have a total sum of zero.

Explains how to count valid subarrays in Codeforces 1692G by tracking adjacent-element constraints and lengths of consecutive valid segments.