Add project files

.gitignore

+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+.idea/

README.md

+# Verify AVL
+
+## Setting up
+
+Clone this repo, edit it locally, and push and upload to Gradescope, exactly as in P1. You should use Java 11 when
+working on this.
+
+You should only edit `verifyavl.VerifyAVL.java` and do not change the method signature. Though, feel free to add private
+methods as you see fit.
+
+## The assignment
+
+Write Java code for an Θ(n) worst-case algorithm that verifies that a tree is actually an AVL tree
+in `src/main/java/verifyavl.VerifyAVL.java`.
+
+You may assume the nodes of the tree have the following definition given in `src/main/java/verifyavl/AVLNode.java`.
+
+You must verify the BST Property, the AVL Balance Condition, and the correctness of the height information. If it
+fails *any* of these properties, return `false`. Otherwise, return `true`.
+
+You can assume that the keys and heights will not exceed `Integer.MAX_VALUE`.
+
+## Grading
+
+We will be running an autograder with **many hidden test cases** to grade your submission. You will receive points for
+each test case you pass. The points will be weighted more heavily on our stress tests, so note that the majority of the
+points you can get require that your code works without question.
+
+## Testing
+
+We've given you a testing harness in `src/test/java/VerifyAVLTests.java`. It reads in `tests.json` and tests your
+verifyavl.VerifyAVL method on the given tree.
+
+The `tests.json` file contains as many test cases as you wish to add, where each case is on a separate line with the
+following format:
+`{"answer": true, "tree": [5,1,[2,0,null,null], [6,0,null,null]]}`
+
+Note that the array representation of an verifyavl.AVLNode is as follows:
+`[int key, int height, [verifyavl.AVLNode left], [verifyavl.AVLNode right]]`
+
+So the example above is of a tree with a root node with key 5, a left child node with a key 2, and a right child node
+with a key 6.
+
+We have provided you with 4 basic test cases:
+
+- A correct AVL tree: `[5,1,[2,0,null,null], [6,0,null,null]]`
+  ![Correct AVL](./img/correct.png)
+- A tree that violates the BST property: `[1,1,[2,0,null,null],null]`
+  ![Incorrect BST](./img/bst.png)
+- A tree with incorrect height labels: `[2,1,[1,0,null,null],[4,1,[3,0,null,null],null]]`
+  ![Incorrect heights](./img/height.png)
+- A tree that violates the AVL balance
+  property: `[2,3,[1,0,null,null],[4,2,[3,0,null,null],[5,1,null,[6,0,null,null]]]]`
+  ![Incorrect AVL](./img/avl.png)
+
+**Note: You should add as many test cases as you need to convince yourself that your solution works. Think about edge
+cases! Your tests will not be graded, but if your code does not work, testing will help you find the problems before we
+grade it.** 
\ No newline at end of file

pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>edu.washington.cs.cse332</groupId>
+    <artifactId>verifyavl-public-21au</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+        </dependency>
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>hamcrest-core</artifactId>
+            <version>1.3</version>
+        </dependency>
+        <dependency>
+            <groupId>com.googlecode.json-simple</groupId>
+            <artifactId>json-simple</artifactId>
+            <version>1.1.1</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+    </properties>
+
+</project>
\ No newline at end of file

src/main/java/verifyavl/AVLNode.java

+package verifyavl;
+
+public class AVLNode {
+    public AVLNode left;
+    public AVLNode right;
+    public int key; // The data element stored at this node.
+    public int height;
+
+    public AVLNode(int key, int height, AVLNode left, AVLNode right) {
+        this.key = key;
+        this.height = height;
+        this.left = left;
+        this.right = right;
+    }
+}

src/main/java/verifyavl/VerifyAVL.java

+package verifyavl;
+
+public class VerifyAVL {
+    public static boolean verifyAVL(AVLNode root) {
+        /* TODO: Edit this with your code */
+        throw new IllegalStateException();
+    }
+    /* TODO: Add private methods if you want (recommended) */
+}
\ No newline at end of file

src/test/java/VerifyAVLTests.java

+import verifyavl.AVLNode;
+import verifyavl.VerifyAVL;
+import org.json.simple.*;
+
+import java.io.FileReader;
+import java.io.IOException;
+
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+
+public class VerifyAVLTests {
+    @Test
+    public void verifyAVLTest() throws IOException, ParseException {
+        // Parse the tests.json file as a json object
+        Object data = new JSONParser().parse(new FileReader("tests.json"));
+        // Cast it to a JSONArray
+        JSONArray jsonArray = (JSONArray) data;
+        // For each element in the JSON array,
+        // i.e. For each test case,
+        for (Object o : jsonArray) {
+            // Cast it to a JSONObject
+            JSONObject test = (JSONObject) o;
+            // Get the actual answer from
+            boolean expected = (boolean) test.get("answer");
+            JSONArray tree = (JSONArray) test.get("tree");
+            AVLNode root = makeAvl(tree);
+            boolean actual = VerifyAVL.verifyAVL(root);
+            assertEquals("Failed: " + tree + " is a " + (expected ? "correct" : "wrong") + " tree but returned " + (actual ? "correct" : "wrong"), expected, actual);
+        }
+    }
+
+    public static AVLNode makeAvl(JSONArray data) {
+        if (data == null) {
+            return null;
+        }
+        AVLNode left = makeAvl((JSONArray) data.get(2));
+        AVLNode right = makeAvl((JSONArray) data.get(3));
+        int key = (int) (long) data.get(0);
+        int height = (int) (long) data.get(1);
+        return new AVLNode(key, height, left, right);
+    }
+}

tests.json

+[
+  {
+    "answer": true,
+    "tree": [
+      5,
+      1,
+      [
+        2,
+        0,
+        null,
+        null
+      ],
+      [
+        6,
+        0,
+        null,
+        null
+      ]
+    ]
+  },
+  {
+    "answer": false,
+    "tree": [
+      1,
+      1,
+      [
+        2,
+        0,
+        null,
+        null
+      ],
+      null
+    ]
+  },
+  {
+    "answer": false,
+    "tree": [
+      2,
+      1,
+      [
+        1,
+        0,
+        null,
+        null
+      ],
+      [
+        4,
+        1,
+        [
+          3,
+          0,
+          null,
+          null
+        ],
+        null
+      ]
+    ]
+  },
+  {
+    "answer": false,
+    "tree": [
+      2,
+      3,
+      [
+        1,
+        0,
+        null,
+        null
+      ],
+      [
+        4,
+        2,
+        [
+          3,
+          0,
+          null,
+          null
+        ],
+        [
+          5,
+          1,
+          null,
+          [
+            6,
+            0,
+            null,
+            null
+          ]
+        ]
+      ]
+    ]
+  }
+]
\ No newline at end of file