Posts (238+)

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May 2026

Deque:Both Ends Without Two Structures

A double-ended queue lets you push and pop at both ends in O(1). How ArrayDeque delivers that in the JDK, and when a deque is a stack, a queue, or a sliding window.

Data Structures

Queue:FIFO, Circular Buffers, and Why a Naive Array Queue Rotates

FIFO as an ADT: enqueue, dequeue, and why a naive array queue slides or wastes space — and how a circular buffer (ring) fixes both.

Linux

Linux dmesg:Read the Kernel Ring Buffer

Hands-on dmesg recipes for everyday work — inspect boot messages, chase hardware faults, filter by level, and watch the kernel live.

Data Structures

Stack:Undo, Parse, and Call Frames Are the Same Shape

LIFO as an ADT: push, pop, peek, and why undo, brace matching, and the call stack are the same layout — implemented with ArrayDeque, not java.util.Stack.

Data Structures

Linked Lists:Singly, Doubly, and Circular Without Losing the Head

How node-and-pointer lists make splice cheap when you already hold the node, why get(i) walks, and how singly, doubly, and circular variants differ.

Data Structures

Dynamic Arrays:Amortized Growth Without Pretending Append Is Always O(1)

How ArrayList grows by doubling, why append is amortized O(1) not a guarantee on the next call, and when a fixed array is the honest choice.

Linux

Linux top, htop, and btop:Watch CPU, RAM, and Load

Hands-on top, htop, and btop recipes — read load averages, find CPU and memory hogs, and triage a busy box in real time.

Data Structures

Arrays:Why Index `i` Is Free and Insert in the Middle Is Not

How a contiguous array makes index i O(1), why insert and delete in the middle slide everything, and how a 2D matrix is still the same layout.

Data Structures

Data Structures Roadmap:What to Learn from Arrays to Tries

A beginner-to-advanced path through data structures: glossary, Big-O literacy, a JDK map, and a living index of every post in this series.

Java

Text Blocks:Multiline Strings Without the Concatenation Soup

Java 15 text blocks (JEP 378): triple-quote multiline strings, incidental indentation, and escape sequences — JSON, SQL, and HTML without + concatenation.