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A collection of programming challenges
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import java.util.ArrayList; | |
import java.util.List; | |
import java.util.Scanner; | |
public class BinarySearchTree { | |
Scanner console = new Scanner(System.in); | |
Node root; | |
public static void main(String[] args) throws Exception { | |
BinarySearchTree program = new BinarySearchTree(); | |
program.runMenu(); | |
} | |
private void runMenu() { | |
while (true) { | |
System.out.println("\n-----------------------------------------"); | |
System.out.println("Binary Search Tree Interactive Menu"); | |
System.out.println("a) Insert"); | |
System.out.println("b) Search"); | |
System.out.println("c) Print"); | |
System.out.println("d) Reset"); | |
System.out.println("e) Exit"); | |
System.out.print("\nSelect an action: "); | |
String choice = console.nextLine(); | |
switch (choice.toLowerCase()) { | |
case "a": | |
insert(); | |
break; | |
case "b": | |
search(); | |
break; | |
case "c": | |
print(); | |
break; | |
case "d": | |
reset(); | |
break; | |
case "e": | |
exit(); | |
break; | |
default: | |
System.out.println("Invalid choice. Try again."); | |
break; | |
} | |
} | |
} | |
private void insert() { | |
System.out.print("Enter a list of numbers (separated by space): "); | |
String[] numbers = console.nextLine().split(" "); | |
for (String number : numbers) { | |
int value = Integer.parseInt(number); | |
if (root == null) { | |
root = new Node(value); | |
} else { | |
root.insert(value); | |
} | |
} | |
} | |
private void search() { | |
if (root == null) { | |
System.out.println("Tree is empty."); | |
return; | |
} | |
System.out.print("Enter a number to search: "); | |
int value = Integer.parseInt(console.nextLine()); | |
if (!root.contains(value)) { | |
System.out.println("Value not found."); | |
return; | |
} | |
Node node = root; | |
while (node.data != value) { | |
if (value < node.data) | |
node = node.left; | |
else | |
node = node.right; | |
} | |
printTree(node); | |
} | |
private void print() { | |
if (root == null) { | |
System.out.println("Tree is empty."); | |
return; | |
} | |
printTree(root); | |
} | |
private void reset() { | |
root = null; | |
System.out.println("Tree has been reset."); | |
} | |
private void exit() { | |
System.out.println("Exiting..."); | |
System.exit(0); | |
} | |
// BINARY TREE PRINTING | |
private void printTree(Node node) { | |
System.out.println("\n-----------------------------------------"); | |
System.out.println("\nVisual Tree: "); | |
System.out.println(node.printNode()); | |
System.out.println("\nPre-Order (TLF) "); | |
printPreOrder(node); | |
System.out.println("\n\nIn-Order (LTF) "); | |
printInOrder(node); | |
System.out.println("\nPost-Order (LFT) "); | |
printPostOrder(node); | |
System.out.println(); | |
} | |
private void printInOrder(Node node) { | |
if (node.left != null) | |
printInOrder(node.left); | |
if (node.right != null) | |
printInOrder(node.right); | |
} | |
private void printPreOrder(Node node) { | |
System.out.print(node.data + " "); | |
if (node.left != null) | |
printPreOrder(node.left); | |
if (node.right != null) | |
printPreOrder(node.right); | |
} | |
private void printPostOrder(Node node) { | |
if (node.left != null) | |
printPostOrder(node.left); | |
if (node.right != null) | |
printPostOrder(node.right); | |
System.out.print(node.data + " "); | |
} | |
// BINARY TREE NODE | |
public class Node { | |
int data; | |
Node left; | |
Node right; | |
int padding = 1; | |
public Node(int data) { | |
this.data = data; | |
} | |
public void insert(int value) { | |
if (value <= data) { | |
if (left == null) | |
left = new Node(value); | |
else | |
left.insert(value); | |
} else { | |
if (right == null) | |
right = new Node(value); | |
else | |
right.insert(value); | |
} | |
} | |
public boolean contains(int value) { | |
if (value == data) | |
return true; | |
if (value < data && left != null) | |
return left.contains(value); | |
if (value > data && right != null) | |
return right.contains(value); | |
return false; | |
} | |
private int indent(List<String> lines, int margin) { | |
if (margin >= 0) | |
return margin; | |
String spaces = " ".repeat(-margin); | |
for (int i = 0; i < lines.size(); i++) | |
lines.set(i, spaces + lines.get(i)); | |
return 0; | |
} | |
private List<String> merge(List<String> left, List<String> right) { | |
int minSize = Math.min(left.size(), right.size()); | |
int offset = 0; | |
for (int i = 0; i < minSize; i++) | |
offset = Math.max(offset, left.get(i).length() + padding - right.get(i).replaceAll("\\S.*", "").length()); | |
indent(right, -indent(left, offset)); | |
for (int i = 0; i < minSize; i++) | |
left.set(i, left.get(i) + right.get(i).substring(left.get(i).length())); | |
left.addAll(right.subList(minSize, right.size())); | |
return left; | |
} | |
private List<String> buildLines(Node node) { | |
if (node == null) | |
return new ArrayList<>(); | |
List<String> lines = merge(buildLines(node.left), buildLines(node.right)); | |
int half = String.valueOf(node.data).length() / 2; | |
int i = half; | |
if (lines.size() > 0) { | |
String line; | |
i = lines.get(0).indexOf("*"); | |
if (node.right == null) { | |
line = " ".repeat(i) + "┌─┘"; | |
i += 2; | |
} else if (node.left == null) { | |
line = " ".repeat(i = indent(lines, i - 2)) + "└─┐"; | |
} else { | |
int dist = lines.get(0).length() - 1 - i; | |
line = String.format("%s┌%s┴%s┐", " ".repeat(i), "─".repeat(dist / 2 - 1), "─".repeat((dist - 1) / 2)); | |
i += dist / 2; | |
} | |
lines.set(0, line); | |
} | |
lines.add(0, " ".repeat(indent(lines, i - half)) + node.data); | |
lines.add(0, " ".repeat(i + Math.max(0, half - i)) + "*"); | |
return lines; | |
} | |
public String printNode() { | |
return String.join("\n", buildLines(this).subList(1, buildLines(this).size())); | |
} | |
} | |
} |
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