leetcode-helper

The generated Tester.java is designed to test the Solution interface. By default, it tests Solution1. To test a different implementation (like Solution2), you must manually update the instance assigned to the solution field within the @BeforeClass setup method in Tester.java.

    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
        /* uncomment to switch solutions */
        // solution = new Solution1();
        solution = new Solution2();
    }

To install, unarchive the .tar, .tar.gz, or .zip file provided. Copy the entire contents of the leetcode-helper-vX.X folder into your working directory.

A clean working directory should contain the following structure:

root
├── README.md
├── build.xml
├── lib
│   └── leetcode-helper.jar
└── problem.properties

Instead of editing problem.properties for every new problem, you can pass the problem.name directly as a property using the -D flag. This allows you to keep a static package.name in your properties file while switching problems quickly.

Examples:

ant generate -Dproblem.name three_sum
ant compile -Dproblem.name three_sum
ant test -Dproblem.name three_sum
ant clean -Dproblem.name three_sum

Once your solutions are implemented, use the following Ant commands to manage the lifecycle:

• Compile all sources: ant compile or ant compile -Dproblem.name <name>
• Run tests: ant test or ant test -Dproblem.name <name>
• Compile and run tests in one step: ant compile test or ant compile test -Dproblem.name <name>
• Clean up: ant clean deletes all source files and .class files for the current problem.

Switching between implementations: By default, Tester.java tests Solution1. To test a different implementation (e.g., Solution2), modify the @BeforeClass setup in Tester.java:

@BeforeClass
public static void setUpBeforeClass() throws Exception {
    /* uncomment to switch solutions */
    // solution = new Solution1();
    solution = new Solution2();
}

Use Apache Ant to generate the necessary Java files for a problem. Running ant or ant generate creates a directory structure containing an interface (Solution.java), multiple implementations (Solution1.java, Solution2.java), and JUnit test files (Tester.java, TesterRunner.java).

To avoid editing problem.properties every time, you can pass the problem.name as a command-line argument using the -D flag.

ant generate -Dproblem.name three_sum

Before generating skeletons, you must configure the problem details in the problem.properties file.

Key configuration fields:

• problem.name: The name of the LeetCode problem (e.g., two_sum).
• package.name: The parent package name for your Java classes (e.g., com.leetcode).
• problem.members (optional): A method prototype for the solution (e.g., private int add(int a, int b) {}). If left blank, the generator uses default settings.

problem.name = two_sum
package.name = com.leetcode
problem.members = private int add(int a, int b) {}

Before generating skeletons, configure the problem.properties file with the problem name and your desired Java package name.

Key fields:

• problem.name: The identifier for the problem (e.g., two_sum).
• package.name: The Java package where your code will reside (e.g., com.ciaoshen.leetcode).
• problem.members (optional): You can provide a method prototype here to pre-populate the solution structure. If left blank, the skeleton will be generated without specific method signatures.

Example configuration:

problem.name = two_sum
package.name = com.ciaoshen.leetcode
problem.members = private int add(int a, int b) {}

The com.ciaoshen.leetcode.util library provides common LeetCode data structure definitions to simplify problem solving.

Available structures include:

• TreeLinkNode: A binary tree where each node has a next pointer to its right neighbor.
• UndirectedGraphNode: A graph node with a label and a list of neighbors.
• TreeNode: A standard binary tree node.
• ListNode: A singly-linked list node.
• NestedInteger: An interface for handling nested integer lists.
• Interval: Represents a time period with start and end fields.
• RandomListNode: A singly-linked list node with an additional random pointer.
• TreeNode (standard binary tree node).

To delete all source files and .class files associated with the currently configured problem, run:

ant clean

Warning: This command is destructive. Ensure you want to remove the files before executing.

The init script reads the following keys from the problem.properties file. Note that the script internally maps these keys by replacing dots with underscores (e.g., problem.name becomes problem_name).

problem.name
problem.pck
problem.util
problem.members