Series 2: Arrays & Algorithms
Fixed-size collections, traversal patterns, searching, and sorting — your first real data structures.
Lessons
2.1: Array Basics
~20 min · Week 6 · Prereq: Lessons 1.4, 1.5
Declaration, initialization, indexing, traversal with for and for-each, default values, and reference semantics. Python lists grow dynamically — Java arrays are fixed-size.
2.2: Searching Arrays
~18 min · Week 6 · Prereq: Lesson 2.1
Linear search (O(n)) and binary search (O(log n)). Pass-by-pass tracing, when to use each, and why sorted data enables dramatically faster searches.
2.3: Selection Sort
~18 min · Week 6 · Prereq: Lesson 2.1
Find the minimum, swap it to the front, repeat. Pass-by-pass tracing, the three-step swap, nested loops, and O(n²) performance.
2.4: Arrays and Methods
~20 min · Week 6 · Prereq: Lessons 2.1, 1.5
Passing arrays to methods, reference semantics with memory diagrams, Arrays.toString/sort/copyOf, and a brief intro to ArrayList.
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