• 30 Days of Code
• Algorithms
• Java

30 Days of Code

Day	Challenge	Points	Solution
0	Hello, World	30	Solution.java
1	Data Types	30	Solution.java
2	Operators	30	Solution.java
3	Intro to Conditional Statements	30	Solution.java
4	Class vs. Instance	30	Solution.java
5	Loops	30	Solution.java
6	Let's Review	30	Solution.java
7	Arrays	30	Solution.java
8	Dictionaries and Maps	30	Solution.java
9	Recursion	30	Solution.java
10	Binary Numbers	30	Solution.java
11	2D Arrays	30	Solution.java
12	Inheritance	30	Solution.java
13	Abstract Classes	30	Solution.java
14	Scope	30	Solution.java
15	Linked List	30	Solution.java
16	Exceptions - String to Integer	30	Solution.java
17	More Exceptions	30	Solution.java
18	Queues and Stacks	30	Solution.java
19	Interfaces	30	Solution.java
20	Sorting	30	Solution.java
21	Generics	30	Solution.java
22	Binary Search Trees	30	Solution.java
23	BST Level-Order Traversal	30	Solution.java
24	More Linked Lists	30	Solution.java
25	Running Time and Complexity	30	Solution.java
26	Nested Logic	30	Solution.java
27	Testing	30	Solution.java

Algorithms

Subdomain	Challenge	Points	Solution
Graph Theory	Bead Ornaments	70	Solution.java
Implementation	Matrix Layer Rotation	80	Solution.java
Warm Up	Solve Me First	1	Solution.java
Sorting	Luck Balance	20	Solution.java
Sorting	Insertion Sort - Part 1	30	Solution.java
Sorting	Insertion Sort - Part 2	30	Solution.java
Sorting	Correctness and the Loop Invariant	30	Solution.java
Sorting	Running Time of Algorithms	30	Solution.java
Sorting	Quicksort 2 - Sorting	30	Solution.java
Sorting	Counting Sort 1	30	Solution.java
Sorting	Counting Sort 2	30	Solution.java
Sorting	Counting Sort 3	30	Solution.java
Sorting	Intro to Tutorial Challenges	30	Solution.java
Sorting	Quicksort In-Place	35	Solution.java
Sorting	Running Time of Quicksort	35	Solution.java
Sorting	The Full Counting Sort	40	Solution.java
Search	Ice Cream Parlor	30	Solution.java
Search	Connected Cells in a Grid	50	Solution.java
Greedy	Grid Challenge	20	Solution.java
Greedy	Maximum Perimeter Triangle	20	Solution.java
Greedy	Beautiful Pairs	30	Solution.java
Strings	Determining DNA Health	50	Solution.java
Strings	Super Reduced String	10	Solution.java
Strings	CamelCase	15	Solution.java
Strings	Two Characters	15	Solution.java
Strings	Caesar Cipher	15	Solution.java
Strings	Mars Exploration	15	Solution.java
Strings	Weighted Uniform Strings	20	Solution.java
Strings	Gemstones	20	Solution.java
Strings	Alternating Characters	20	Solution.java
Strings	Beautiful Binary String	20	Solution.java
Strings	The Love-Letter Mystery	20	Solution.java
Strings	String Construction	25	Solution.java
Dynamic Programming	The Coin Change Problem	60	Solution.java
Bit Manipulation	Lonely Integer	20	Solution.java
Bit Manipulation	Bit Manipulation: Lonely Integer	20	Solution.java
Bit Manipulation	Sum vs XOR	25	Solution.java
Bit Manipulation	Maximizing XOR	30	Solution.java
Bit Manipulation	Sansa and XOR	30	Solution.java
Bit Manipulation	Counter game	30	Solution.java

Java

Subdomain	Challenge	Points	Solution
Introduction	Welcome to Java!	3	Solution.java
Introduction	Java Stdin and Stdout I	5	Solution.java
Introduction	Java If-Else	10	Solution.java
Introduction	Java Stdin and Stdout II	10	Solution.java
Introduction	Java Output Formatting	10	Solution.java
Introduction	Java Loops I	10	Solution.java
Introduction	Java Loops II	10	Solution.java
Introduction	Java Datatypes	10	Solution.java
Introduction	Java End-of-file	10	Solution.java
Introduction	Java Static Initializer Block	10	Solution.java
Introduction	Java Int to String	10	Solution.java
Introduction	Java Date and Time	15	Solution.java
Introduction	Java Currency Formatter	15	Solution.java
Strings	Java Strings Introduction	5	Solution.java
Strings	Java Substring	5	Solution.java
Strings	Java String Compare	10	Solution.java
Strings	Java String Reverse	10	Solution.java
Strings	Java Anagrams	10	Solution.java
Strings	Java String Tokens	15	Solution.java
Strings	Pattern Syntax Checker	20	Solution.java
Strings	Java Regex	25	Solution.java
Strings	Java Regex 2 - Duplicate Words	25	Solution.java
Strings	Java Regex 3 - Username Checker	20	Solution.java
Strings	Tag Content Extractor	20	Solution.java
BigNumber	Java BigInteger	10	Solution.java
BigNumber	Java BigDecimal	20	Solution.java
BigNumber	Java Primality Test	20	Solution.java
Data Structures	Java 1D Array	5	Solution.java
Data Structures	Java 2D Array	10	Solution.java
Data Structures	Java Subarray	10	Solution.java
Data Structures	Java Arraylist	10	Solution.java
Data Structures	Java 1D Array (Part 2)	25	Solution.java
Data Structures	Java List	15	Solution.java
Data Structures	Java Map	10	Solution.java
Data Structures	Java Stack	20	Solution.java
Data Structures	Java Hashset	10	Solution.java
Data Structures	Java Generics	15	Solution.java
Data Structures	Java Comparator	10	Solution.java
Data Structures	Java Sort	10	Solution.java
Data Structures	Java Dequeue	20	Solution.java
Data Structures	Java BitSet	20	Solution.java
Object Oriented Programming	Java Inheritance I	5	Solution.java
Object Oriented Programming	Java Inheritance II	10	Solution.java
Object Oriented Programming	Java Abstract Class	10	Solution.java
Object Oriented Programming	Java Interface	10	Solution.java
Object Oriented Programming	Java Method Overriding	10	Solution.java
Object Oriented Programming	Java Method Overriding 2 (Super Keyword)	10	Solution.java
Object Oriented Programming	Java Instanceof keyword	10	Solution.java
Object Oriented Programming	Java Iterator	15	Solution.java
Object Oriented Programming	Calculating Volume	20	Solution.java
Exception Handling	Java Exception Handling (Try-catch)	10	Solution.java
Exception Handling	Java Exception Handling	15	Solution.java
Advanced	Java Varargs - Simple Addition	15	Solution.java
Advanced	Java Reflection - Attributes	15	Solution.java
Advanced	Can You Access	15	Solution.java
Advanced	Prime Checker	25	Solution.java
Advanced	Java Factory Pattern	15	Solution.java
Advanced	Java Singleton Pattern	15	Solution.java
Advanced	Java Visitor Pattern	40	Solution.java
Advanced	Java Annotations	25	Solution.java
Advanced	Covariant Return Types	20	Solution.java
Advanced	Java Lambda Expressions	30	Solution.java
Advanced	Java MD5	30	Solution.java
Advanced	Java SHA-256	30	Solution.java